Now to be fair, we're talking about within a fictional world where there actually are other races on other planets. That said, while I completely understand things like "the white savior" and whatnot to be avoided (to offset the past) when it comes to Earth-based stories, when it comes to alien races I don't mind a little institutional species-ism. I mean everybody loves Guardians of the Galaxy and that's clearly an example of the guy from Earth going and pulling together others to save the day. It's fantasty, it's OK. No real aliens are being offended. They have much bigger problems with constantly being treated as evil invaders.
That said, there are certainly plenty of counter examples - Star Wars doesn't have an Earthlings at all.