I'm a casual gamer, and I find it fun to play online, and the teamwork element helps in team games - wheras with COD it seems like you need to be some fat geek expert who plays 16 hours a day to have any chance of enjoying the game. And the team element in COD sucks.. even in team mode, it's every man for himself. Boring.
If anything it's the opposite. COD is made for casuals.