It's really not, even if it's the reality of the world outside of the story. How many movies have had this "common trope" from the last two decades aside from the first Avatar? I can name dozens with strong brown wahmin at the forefront, but it's rare to even get a white male protagonist presented in a consistently positive light, let alone treated as a savior. Even The Great Wall, a movie I 100% expected to have the trope, actually subverted my expectations to my surprise, having the white man be a big help but hardly the lone hero that all the Chinese had to cower behind.
It was common fifty fucking years ago, maybe. Yes, Jake is a race traitor bitch, that's why I find it funny how you felt the need to complain about it not once but twice.