sorry but when the stereotype is a planet of black savages that kidnap a white woman, it's racist.
Why? Because being savage and kidnapping women is a classic black behavior pattern in reality and thus cannot be mentioned out loud? Or because it isn't? Neither concern makes any sense - savagery or kidnapping aren't dependent on skin color, and any attempt at trying to pry apart what was never joined is only indicative of a fixation amounting to a rather disgusting brand of racism.
How would the episode have been better if the locals were pink or purple in color? I guess "multi-ethnic" would make sense in this particular case, because the culture is shown to have working global transportation (they even have transporters), but it's awfully racist to insist on multi-ethnicity just for the sake of never showcasing any single ethnicity...