You’re saying yourself that Finn being black didn’t affect the plot in any way. Are you now suggesting that every time an actors ethnicity doesn’t influence the story, it should be the standard to chooose the white one? Does there always need to be a special reason to have a non-white (or non-male, non-hetero etc.) character? The people outside don’t have a specific reason to be asian or hispanic or whatever, they just are the way they are and for Star Wars, this is now unthinkable?
Also, Star Wars has a tradition of being inclusive since 1980, do you complain about Lando, too?