His sister was dating a black man. I suspect that’s the why in all this. She and boyfriend were the targets and the other people were the collateral damage.
Sure, that might be a disconnect with him protesting the KKK but we don’t know who asked him to go to the demonstration or why he was really there. Of course, he could be ok with blacks up to the point of having sex with his sister.
How do you know he was dating a black man?
I have heard that surmised but there are no pics.