its down to a few things,
first of all its very popularity holds it up to more scrutiny,therefore more attention positive and negative,
then there's the already mentioned fact that its becoming a yearly "EA sports style" pisstake of releasing the same game with different skins and charging full whack for it,then you have the fact that the publisher are at the forefront of a SHITLOAD of the dickiest dickmoves in dicktown at the moment vis a vis ripping off consumers as much as humanly possible,so you get backdraft from that spilling onto the game,
then you get the fact that a good percentage of cod fans are absolute fucking eejits who do themselves or the game no favours with their antics.
on a related note,about the gun thing,I have a couple of vids on youtube of me firing the SPAS 12 shotgun and I get a SHOCKING amount of comments from cod players talking complete arse about the weapon,its gotten so bad I dont reply to them anymore,got sick of replying to the same bullshit and fallacies again and again,so yeah there are more than a few players who think that because its a game loosely based on reality that it is like a frigging manual for weapons,facepalms all round.
tl/dr's are for retards. if you cant read don't post.