If someone I know and like supports politicians, child molesters, cops, Nazis, etc., I don't want to know. I expect such from people I don't like, so they can't really disappoint me. But people I like, I expect to be better than that. I don't want to be disappointed in them.
Unfortunately, that's not how real life works most of the time.
Most people have been so brainwashed that they see the bad guys as good guys, and when one of these bad guys is exposed, they see it as a "bad apple" instead of an accurate representation of the type.
I don't often point this out or say "I told you so"-- but I sure do think it often. And then I go on with my life, with a slightly lower opinion of someone's intelligence and ethics.