Technically, a lot of the most annoying fanbases are exaggerated especially by people that are against them. For example, CoD's community is actually not as annoying as most would make it out to be, it's just we hear so much about how some people can be idiotic mic-spammers that we assume that to be the case for everyone. Obviously, you will never hear how you met some nice people on CoD because that's not worth talking about. It's also due to the most annoying people in a certain community being the most vocal to people outside of it. Does that mean CoD and Halo are devoid of these annoying stereotypes? No, we wouldn't be talking about this if it was completely false.
OT: CoD fanboys do annoying me, but recently, I'm starting to get annoyed by Bioware fanboys. Not only do they express a flavour of elitism that is almost equal to the "hardcore CoD fan", they act like real snobs and express a level of pseudo intelligence, flailing their supposed superior choice in games and calling anyone out for disagreeing with them by calling them "mindless sheep". Just like a previous user said, it's amusing that they express such hostility towards other people's choices in love interest on their own forums, it's no wonder trolls refer to Mass Effect as "waifu dating simulator".