I always thought coloured was the politer version of black
You know, coloured = person of colour. Welp. But I am also not from the US so maybe that's why.
The problem is, people pay more attention to the terms used than the actual content of the speech these days. You can be racist and don't use any racial slurs ya know? That won't make you any less of a racist. Using "questionable" words when you don't mean any harm won't make you a racist either. Instead of blindnessly attack people for usage of "wrong" words maybe you should try to figure out their actual intentions first?