All of this still leads to my main point: In order to (effectively) counter (the effects) of a sniper, you need your own sniper.
The whole point of the paragraph you are referencing was explaining that that's not true. You need either SOME unit that trades efficiently to counteract the manpower bleed OR you need an army composition that is oppressive enough to just shut down the sniper players mapcontrol. Most games vs Snipers will result in counterplay based on the latter approach. A sniper is simply a trade off between manpower bleed and stopping power/mapcontrol.
Even if you don't follow any of the specific "counterbuilds" a sniper is far from an autoloss. The problem is that a lot of people think like you and want to kill it because otherwise they have to take the bleed. They immediately start throwing shit at it stupidly. There are very solid players who fall into this trap.
But let's be specific because I genuinely think what you're describing in terms of having to counter the sniper is just not representing the reality of the game at all. I wanna go through each matchup and describe what reaction to a sniper is likely gonna happen and whether it's likely to be succesful. All of this is pretty uncontroversial among competent players I'd say. Most of it also doesn't require a big deviation from the playstyle that is already established for each faction anyways. On a side note: You can't exclude doctrinal abilities/units just because they are doctrinal. Doctrines are essential for most factions and USF immediately becomes trash without their meta doctrines. This is not unique to countering snipers at all.
Ostheer Sniper vs UKF:
Let's start with the one matchup where the sniper is probably overpowered:
1. Tommy blob with quick 5men to continuously overrun the wehrmacht player. Goal is not to give the wehrmacht the time to use the sniper by decisively winning engagements and forcing retreats.
2. Early bren carrier to cause counterbleed early on into quick AEC to counter the inevitable 222. Later on typically commandos to threaten the sniper and get wipes that counteract the bleed. Alternatively Countersniper.
Ostheer early Sniper vs USF
Not much changes here compared to the same matchup without a sniper. USF is bound to bleed to death unless their light vehicles pay off. Ironically the sniper makes it much easier to succesfully play LVs because there are 1.5 fewer fausts and a juicy target.
1. 2 Rifles -> WC51 -> LT -> M20 -> Cav rifles -> Stuart will result in complete and utter destruction of early sniper builds.
2. Standard 3 Rifles -> LT -> M20 -> 50cal -> Stuart will also likely result in a win vs early sniper. You'll have great map control solving your biggest worry as US, namely preventing the P4 to force you into Captain backtech.
Ostheer late Sniper vs USF
Ostheer has 340 mp to spend on a sniper? The game is over because you didn't pressure him enough. This has nothing to do with the sniper. At this point you are bound to be bled to death whether it's by LMG grens or LMG grens + Sniper is irrelevant.
Ostheer early sniper vs Soviets
Build 3-4 cons -> auto win the game
Ostheer late sniper vs soviets
Pretty much non existent in top level games. You literally named the one exception which took place on the map position that is by far the best for sniper builds (south langres). Can be good in lower level games (I see it now and then in my own games vs equal players) but doesn't change the flow of the game that much. It just puts a timer on con sandbag camping which is the main point. But cons aren't very bleedable which is why it's so rarely seen.
Early Soviet Sniper vs Wehr
Just play normally and baselock the soviet -> gg
Late Soviet Sniper vs Wehr
Idk about this one. Literally never happens.
Early Soviet Sniper vs OKW
blob-> absurd map control -> rush any vehicle and keep blobbing -> gg
Late Soviet Sniper vs OKW
Gives you the edge in fighting power you need to overrun the soviets mandatory double ZIS. Never happens either for that reason.
"Early" brit sniper vs OKW
Blob -> Luchs+Puma -> gg
Late Brit Sniper vs OKW
Can be decent on certain open maps. You need to be careful to do focused attacks and overrun the Brit in waves. This is by far the most complicated matchup and I'm not sure how viable the brit sniper is here. However the brit definitely becomes very fragile and vulnerable to well times OKW blobs. In a static game JLI are good because they force your opponent to screen for the sniper and get his in a bad position to uncover the JLI so you can start taking apart his meatshield. Double ISG camp with smoke spam can be good in teamgames. (Smoke is SEVERELY underused especially vs snipers).
Your second point has a lot of claims which I cannot verify or are rather subjective. What stands out however is this sentence: "However once Ostheer gets into a clear winning position Sniper can be the final nail in the coffin."
This is what Kimbo did and is also testimonial to the power of a sniper in a game designed around comebacks: they shut the door completely. Unless you get your own sniper and yada yada yada.
What I said in the 2. paragraph may have sounded like forum warrior blah blah but it's pretty much just a summary of what the vast majority of decent players agree about.
If you're already bleeding to death a sniper can be the final nail in the coffin. If you are already struggling for map control a medium tank or LV (depending on the game stage) can be the final nail in the coffin. If you're fuel starved and turtling with double pak a katyusha can be the final nail in the coffin etc.
Third point: ad hominem. Your statement attacks the character of those who are against snipers and furthermore could easily be turned around (also something I planned to do in my first post) as follows: most people defending snipers are those who abuse them the hardest.
Objectively true? Yes but does it serve any other purpose other than attacking your character (or those defending snipers)? Nope. As such I removed it from my first post and I think your statement should never have been in your post as well.
Ok I accept that. I won't delete it so our conversation doesn't become nonsensical but consider it taken back. Just as an explanation: Imo my statement is relevant to the debate because people who can't use snipers don't actually have the same intuitive sense for the disadvantages that come with it. E.g. how much harder it becomes to resist map pressure. They also fall into the aforementioned trap of "sniper raging" more frequently in my experience.
Your fourth point still misses the mark. Which is that an early LV's is not a counter to (the effects of) the sniper (not to mention said sniper can be build after the LV rush) since the bleed will continue. Early map control is nothing compared to bleeding manpower like a stuffed pig (the entire game, mind you), which is what snipers do.
Mapcontrol is absolutely essential and will eventually be converted into an MP advantage because you will have non bleedable tanks before your opponent which will also give you even more map control etc. CoH2 is a game of snowballing. The sniper enables your opponent to snowball. Tbh I shouldn't even say that LV rush is a specific "counter" to the sniper. It's part of every game. What I'm trying to explain is that the sniper becomes a big disadvantage during the LV stage of the game because 1. It gets threatened by them so it will be much less efficient. 2. Whatever LV is dominating will cause counterbleed. 3. The player dominating in the LV stage will gain superior map control.
Your fifth point acknowledges the indirect fire in teamgames, so there is that. But you missed the part where snipers can "enhance" sandbag+dual MG camping. As such, my point here is as follows: snipers don't fix this issue.
Well they just don't. Nothing else I can say. I'll just have to argue from authority here and say that from playing the game I know that a sniper doesn't lead to more sandbag camping. It's like obviously untrue. Snipers lead to other not so pretty playstyles like blobbing or constantly hiding behind shotblockers or house jumping but they don't facilitate sandbag camping. They prevent it. I just know from playing the game but I guess if I had to explain it theoretically it would look like this: Sandbag camping happens when two sides have roughly the same army size so the side that would benefit from close range can't charge the sandbags without losing the engagement and the other side has no reason to charge. When a sniper is on the field one side can't camp because they will be sniped and the other side can charge sandbag positions because the opponent has less stopping power. Soviet sniper vs OKW is the best example. Usually I wouldn't necessarily wanna fight penals or cons at close range but when there's a sniper on the field I'm suddenly gonna rush every single soviet inf squad I can spot with my volks blob just because I know i have superior numbers.
Your sixth point: my point here is twofold: no other unit forces this dynamic on the opposing player and more importantly, one side has to exert a tremendous amount of micro to mitigate the effects of a singular unit on the battlefield (unless they get their own sniper, is this getting old yet?). Which also comes back to my second point: a sniper on the field forces the entire game into countering (the effects of) that sniper.
Here I'll have to go back to my ad hominem argument but in a different context. Most people can't play snipers. Among high level players a significant percentage still can't play snipers. A lot of people start playing like shit with the rest of their army once they have to use the sniper. On a good day a B-Tier player can reach Top tier levels of play with his army. After all the challenge isn't microing any singular unit but rather the multitasking you have to do to make you army act coherently. Sniper is different. There's people who can play it on a certain level and people who can't. I can play a sniper raesonably well but I won't reach god tier sniper micro by a fluke. I will however occasionally reach top levels of play with my other units. So yea I really think the opposite is true and the bigger micro tax is placed on the sniper player or at the very least that the micro tax is even.
Edit: I wanna add one more thing: There are actually plenty of units that require you to build a specific counter. Aka every light vehicle in the game. T70 quite literally forces the wehrmacht player into a pak. There are also plenty of units that cause unopposed manpower bleed. Have you see how high level 4v4 teams use 120 mm mortars? They just cause raw bleed and there's nothing you can do other than punish them for having invested that much mp into a unit that has no stopping power.