A plurality of voters in our outdated First Past the Post election chose this. This is the primary causation. Too many voters stayed home and too many swing voters wanting change were too easily misled by the Conman. Misled because they didn't understand tariffs, among a bunch of other things (fascism, wokeness, etc.).
But to your point, the States are learning the hard way despite the words and actions of voters like me.
You're right. Racism is a tough drug to quit. To quit, it starts with recognizing one's own racism. Sure, some racists know and are even proud of their racism. But most racists don't know or understand how racist they themselves actually are. They think "Well I'M not racist!" and then think voting for the racist candidate is unrelated.
I think most Donvict voters fall into two camps regarding racism: 1) They're too naive to recognize that donOLD was/is a racist or 2) They don't recognize their own racism. There's a minority of them that are knowingly or blatantly racist.