It was mentioned in a 1UP article on the possibility of a remake in another thread. Can't remember which one right now (and it might have been Velo who linked it actually, I'm not 100% sure). And though the Japanese obviously had nothing to do with 9/11, terrorism is still a touchy subject in the US, and Id imagine there's a certain weariness to go there given the cultural differences. They may be a bit unsure how such topics being treated in a somewhat heroic light would be received over here just because they aren't American. I imagine it would be a bit like me considering making a game about the holocaust but not really being sure how Israel would react.

Terrible example, but it's all I got.