I think the only reason people have a problem with it as opposed to the GTA series is that in GTA, you ARE a bad guy, doing illegal things and its fun because according to the game thats what you should be doing.....in MW2..ur a soldier, a good guy, suppose to fight against terrorists...but in the airport situation..depending on how involved you let yourself get in the game..it can really "erk" you with what you have to do...especially with the ending to that level.I still don't get the hype around that level. How is it different that GTA where you can kill prostitutes, police officers, or people randomly walking around.
In the original modern warfare you took on the role of the president of an unnamed middle eastern nation. You are dragged through the streets of your former capitol city, beaten with the stock of an AK, watch unarmed prisoners be executed and are powerless to stop it. You are then knocked out and dragged to a pole in the middle of the town square, tied to it and executed.
In another sequence the villain of the game detonates a nuclear bomb in the middle of a the aforementioned middle east city. You are playing the role of a Marine at this point who has confirmed his status as a hero by rescuing the pilot of a downed troop carrier helicopter when a nuclear bomb goes off. Your evac chopper crashes and you crawl through the destroyed city bleeding out until you are dead.
Neither of these scenes warranted this much vaunted 'you can skip this it's okay because it is pretty fucked up' option.
Finally, what about the torture scene in the game? I haven't seen that plastered all over the news.
Honestly, it's just a video game.