That is an interesting question because the U.S. in particular still tends to treat the subject as taboo, which is really ridiculous at this point. Hell, I remember when Superman Returns came out, they said that Superman came off "gay" in the movie, which was ridiculous and I believe solely generated by a**holes who had a problem with Bryan Singer being gay.
Now, if they were insinuating that Superman came off catatonic or wooden in that movie, well, that'd be a different story.
But anyway, I would have no problem if the actor playing Superman was gay. I can't speak for the rest of America, though.