Let's say you give a Hindi greeting to an Indian guy who's second-generation American and doesn't speak Hindi. What's the worst that can happen? Well, if he's a SJW he'll spread your name on the internet as a "racist asshole". But if he's a normal person, you get past the misunderstanding quickly, and plus he knows that you know enough about his culture to have learned its language, and he might even appreciate that.
Our primate relatives are racist and sexist. What makes us think that we can not be?
Pretending to ignore race/sex differences out of some misguided attempt to be polite or "color blind" or "culturally neutral" does no one any good.
By "racist", I mean "actually despises others because of their ethnic background", not "has the odd awkward or confusing moment of ethnic / cultural misunderstanding".
Similarly, by "sexist", I mean "actually dislikes or has contempt for the opposite sex".
Of course the bar for these words has been raised to the point where the political Left can call someone a racist because they do not support a specific affirmative action policy, or a sexist because they disbelieve certain cooked-up statistics about the alleged "pay gap" between men and women.