Haha, yeah, that was pretty obvious from your first comment to be honest. Again, I don't think anybody has a duty to do anything. And I think "fight" is entirely the wrong framing for this. Though, sadly, that's the framing so many so-called antiracists like to use nowadays, so it's understandable that that's the phrasing that gets used.

It's not about moral authority or taking an ass-whooping, I'm sure you understand very well that if somebody disagrees with you and they start yelling at you, they're almost never going to change your mind. Never mind if they start throwing hands.

If you want to do something, just talk to people. Relate to them. Say to them whatever somebody could have said to you all those years ago that might have gotten through. It's very, very rarely going to be some lightning bolt moment where the racist scales fall from someone's eyes. Just invite people to think. Racism and thinking can't really coexist.