Why are people pretending that Superman being seen as American is the biggest problem?

Man of Steel was pretty much AMERICA FUCK YEAH in content, with the movie being used as an ad for recruitment, Superman and the US military learning to work together to save the day from terrorists from outer space, and Superman declaring he is American.
That movie also came after War on Terror and right before Trump presidency, with the film often being called as the Donald Trump of capeshit movies.

Reminder that this movie is for chuds.