This one irks me just because the logic behind it is so bizarre. How is "people of color" a polite, respectful term, while "colored people" is incredibly offensive?
I saw someone on a forum I visit get jumped all over for being unable to distinguish between the terms and it was one of the strangest things I'd ever seen. People who were using "POC" every other sentence suddenly became incensed when the order of the words was innocently reversed by someone who apparently hadn't read the most current version of the SJW Handbook.
I don't think it's about finding a non-offensive word/phrase, it's about continually changing the word/phrase.
Consider the progression:
Crippled
Handicapped
Disabled
Differently abled
Special Needs
Good Needs (seems to be the new on, in our kids' school anyway)
As each one becomes the well-known word to describe the group, the group and their advocates start to realize that jerks are using it as an insult, so it's time to change it to again.
It will never stop.