You’re making it too complicated.
“Racist” is a 20th century neologism with no fixed meaning. Since it has no fixed meaning, and it’s intended referent, “race”, has pluriform meanings, there’s really no intellectually sound way to defend oneself or another against the charge.
It’s all postmodernism. A man feels like a woman - he is one. Someone feels you are a “racist” - (or derives advantage from pretending that they do) - you are one.
Try, at least in your interior life, to eliminate the sting that goes with the charge. It really doesn’t mean anything.
>>“Racist” is a 20th century neologism with no fixed meaning
In the 20th century, it had a fixed meaning. In the 21st century, it has turned into the word with no fixed meaning that your post describes.