At some point it comes down to incentives, to not shun such terrible people just helps increase their influence. Accepting their money makes it look like you think what they did isn’t bad. Terms like greenwashing exists just highlight this problem, we have to make it clear it’s unacceptable to behave like that and that you can not buy your way out of consequences.

It’s basic risk assessment

Literally everything else you’re talking about is solved by ensuring due process is followed