Some people take things too far, though in fairness just having a white/black savior role isn't analogous to the standard 'white messiah' storyline. Generally you're looking at an indigenous people/group. Introduction of the lead character to the group, and through attrition, acceptance of that character and usually the character gains some leadership/respect role while teaching his new friends a thing or two about his culture and vice versa, laughs and awkward moments ensue. Usually some unlikely love story unfolds. Yada yada yada.
You can read into that however you feel, but it is a very often repeated theme in many major motion pictures. Is it racist ? In my first post I stated that was a bit harsh, are there racial/cultural undertones, absolutely, that is the whole idea of the story. That differences can be beautiful, or ugly depending on what side you view them from. I honestly think it really depends on the respect the film has for the people that are penetrated (usually in multiple ways, go blue weiner). In the case of blue aliens that are cat-like, and longlegged, I hope for at least one 4 giant-mech on 1 fem-cat gangbang.