I've never liked war games but I'm very glad I got CoD4.
The point about CoD4 is exactly that it's just such a war game. I thought I could ignore it and just enjoy the game, but the pictures during the setup already showed US and British troops slaughtering Arabs and bombing their cities and having structural and infrastructural damage beyond mere numbers, and what we have the nice term "collateral damage" for in the millions, for that silly war we all know had no point in the first place (no WMD, no ties to Al Kaeda, all lies and oil). I can't see myself fighting on the wrong side in that one.
Not that the other side woulnd't be a wrong side either, what with Saddam's dictatorship and all. But I won't delve into politics again here. Just this: The game has a way too realistic setting to be enjoyable for me, I imagine. After installing it I haven't touched it anymore.
(And yes, I do know the setting is fictional and the parallels to current-day wars are merely on the surface. But the graphics are realistic enough and the real wars are close enough, I don't think I can look beyond that and stay within the happy illusion that what I'm playing has nothing to do with actual wars.)
I never touched Return to Castle Wolfenstein either, and couldn't stand playing BF2 for too long. I just have this thing with overly realistic games.