Am I the only one who thinks this?

Every time I go online to play MW2 and I see there is about three people in the lobby with the same clan tag in the opposing team I make it my mission to destroy them in the match. I just don't like clans, I mean its ok to group up with buddies and play but one time in team deathmatch there were three guys in the same clan in my team. So when we lost the three guys said "our team sucked thats the only reason we lost", maybe it had something to do with the fact that you guys stayed in one corner. I also despise people who say there MLG because there basically saying they have a skill that will probably not be useful in the future.