It's been racist for several decades, and it's not benign at all.

The logic behind this change is that it puts the PERSON first. You're first and foremost a person, and then after that you're using a descriptor. Usually this terminology is used to be collective of anyone not white, because it's used in context of the unique experiences that anyone not white has to navigate all their life, at least in US. Examples such as people of color are more likely to be pulled over by police, people of color have a harder time finding makeup that suits their skin tone, etc.

If you're just talking about an individual or a group without that context it's much more common to hear them just referred to as black, or whatever ethnicity they are, if its even relevant.

I know it can all feel arbitrary when words are suddenly not okay anymore, but I think it is because these acceptable terms for marginalized people eventually get used so often in a hateful context, they may try to adopt a new term. I mean many women now cringe hard and go on alert for red flags whenever they see women referred to as female, maybe can't even stand it anymore despite the context, because it has been so consistently used by a very specific type of person.