I would say that probably the second one highlights some of the outsider similarities, especially with gay people, a bit more, one scene in particular. The first one does as well, but the newness of concept of mutants, in the movie's world, is different. The opening scene sets up nicely the sense of prejudice in the first one, while the second one takes it further and has more of a parallel to the stigmatization of LGBTs.
Juan