As far as I can tell, the point is that there was NO actual reason why they hated him apart from they didn't know him. Once they knew him, they didn't hate him.
The ones that changed their point of view, eventually just realised they had no remaining reason to hate him. And by extension it was irrational to automatically hate every other black person they didn't know yet.
It was his attempts to understand them, that helped some of them understand him. As he points out though, there were plenty of klan members that this didn't work out with though.
It obviously takes some level of self awareness/reflection to change your mind like that.
The ones that changed their point of view, eventually just realised they had no remaining reason to hate him. And by extension it was irrational to automatically hate every other black person they didn't know yet.
It was his attempts to understand them, that helped some of them understand him. As he points out though, there were plenty of klan members that this didn't work out with though.
It obviously takes some level of self awareness/reflection to change your mind like that.