Tbf, as a young child I was told to say coloured after I stumbled over the question of white and black skins. I knew enough that it was a touchy subject. Tbh, the average person really ought not be bothered about white and black. We are just people. What we say to police if we're witnesses to a perpetrator of a crime, I don't really know anymore. The Police say white, black, etc.., I think. But categorising people by a colour is considered offensive. Nobody is allowed to be brown, yellow, or red anymore, so why should it OK for people to be categorised as white or black.? Because the people being categorised generally say it's OK. It's with agreement. It's also shorthand. I suppose we could say Caucasian, ******* etc... but they don't really apply as a official coverall because they're inaccurate. Besides, acceptable words are as political as the changing wind direction.
15-20 years ago you couldn't say Chairman or Postman, for example. It had to be Chairperson, or even Chair... Even the Postperson became Postie. Now they've crept back in under the radar. Strangely, during the same period, actors and actresses became actors. I think they've stayed that way. Who is to know what will be acceptable, just around the corner, given that the global village we live in changes its mind constantly. We think we're moving towards a better version of what is acceptable, with each change in the wind. But actually, it's more like to steps forward and one step back. Sometimes, it's the other way around.