It would be preferable that people who act and live like Trump were completely unwelcome in the Democratic Party, such that Party leaders rebuked them, and their political donations were rejected as well. That’s all I’m saying. Have some standards. Hopefully that’s changing for the better.
He was a self proclaimed Democrat ~33 years ago (presumably voted, but definitely gave donations) and is, 33 years later, completely unwelcome in the party. Either the party moved away from him, or he moved away from the party. The first is the path your desire, but either case is good. People with Trump's world view do not have a home in the Democratic party.