Not necessarily. Allied mainline infantry is supposed to be better. The fact that PGrens arrive at a point were they do not have combat bonusses yet completely reverses this infantry advantage that Allies have over Axis. That's what his post says. And he still did not state anything with spamming.
I can also say a 7 minute Allied medium negates the idea of OKW having their LV power spike. Using Osttruppen negates sniper play. Blobbing MGs frontally negates the idea of infantry suppression. Does not mean that a blob is equal to an MG.
Still, this is a pretty nit picky wording discussion and has nothing to do with the actual topic.
Imo "pretty much negates the idea that Allies have better "mainline" infantry" says that Ostheer have better mainline infatry because of PG since it talk about the "idea" of better mainlines infatry and not negating the advantages of a better mainline. The argument is that Allies to not have better mainline infatry not that any advantage from mainline infatry in negated by other factors.
But there is no reason to dwell on this, I am pretty sure that Godguy cam explain what he meant to say if he wants to.
The important thing here that the number of Pg used per game in WC2020 seems to be small.