Majority is too strong of a word here. I honestly haven't even heard of anybody being so angry at the game to turn it off when he gets the side he doesn't like on a map.
Also, maps don't have to be symmetrical to be ballanced. Just like assymetrical factions are ballanced by having different strenghts and weakneses that players try to use or overcome maps can give different sides/teams/players different bonuses and initial goals. When a map feels different to play depending on the side, it is almost as if you had twice the number of maps! And in games like coh2 where players play the same game mode for many hours it is important to let the game change from one match to another or the game gets boring quite quickly.
I do agree maps don't always have to be symmetrical to be good/balanced. Its just easier to balance a more symmetrical type map. Some of the symmetrical maps have been pretty bad also (Sittard Summer/winter is the biggest example I can think of). Sometimes though I feel the asymmetry of maps in coh2 does more bad than good, being from a competitive gaming background for most of my life, however, I might be a little bias towards the more competitive symmetrical maps we see in other games.
I feel like asymmetry can work as long as they do not mess with certain "must have" map attributes (IE: Same timings to center of map, no game-changing one-sided buildings, single-sided cutoffs, unfair or uneven cover that favors one side.) The biggest complaint I have is maps like Moscow which have a brutal cutoff for north for the north favored fuel while having no equivalent for the south side which is unfair.
I havent alt f4ed a match bc of a map so yeah an exaggeration my bad on that. It is still pretty upsetting to get some bad map spawns though and I can say I have quit the game after some matches after getting screwed over and over by map choice (Use to happen after getting Sittard Summer after vetoing it and going through a painful hour-long artillery fest.)