It would depend on where the friends' views are rooted. If the friend is saying "My uncle is a cop who's never done anything wrong and he doesn't deserve to be

It would depend on where the friends' views are rooted. If the friend is saying "My uncle is a cop who's never done anything wrong and he doesn't deserve to be lumped in with the ones causing trouble", I could actively sympathize with that. If the friend is saying "I still think it's only a few bad cops and that the protesters are causing more trouble overall than the cops", I would tend to think that person was misinformed and maybe try to share new information with them if I thought it would make a difference, but I would also leave it be if I had to for the sake of the friendship (this is my situation with my parents). If the friend is saying "Strong-man governments are great, people should bow down and stop trying to hold the police accountable, they shouldn't have to be accountable to anybody", then that would tell me something about the person's moral center and I don't see myself wanting to remain friends with that kind of person at all.