Because it is them that are the racists, but they won’t admit it.
I’m a white (mostly), traditional, middle-class, Christian man. Raised poor, worked through college, etc. Around 20 years ago, the then girlfriend (now, unfortunately, wife) of a friend branded me a racist in her mind. I met all the requirements. Except, of course, for there being any indication that I harbored ill will or thoughts regarding other races. Her daughter gave birth to a little girl. She was black. And we (the little girl and I) totally hit it off. We have all had that experience in which both the adult and the infant/toddler just naturally take to one another in a unique way. I was her favorite visitor, and once she learned to talk, we had some pretty wonderful conversations. Then one day her grandmother commented that it was so odd that she and I got along. “What do you mean?”, I asked, honestly. “Well, you’re conservative and white, and she’s black!” Oh boy.... And this woman honestly believes she is “woke” and the pinnacle of correct political behavior. She has since instilled in her granddaughter a hatred of white people. Except of course for immediate family. Racism held deeply, revealed....