Someone in the old thread wanted to know why Kirk's death is perceived to be a turning point. I think it's because he wasn't a politician or Hollywood A-list celebrity, for whom the threat of violence comes with the territory. He was political, yes, but lots of people are. He said provocative things, but again, lots of people do. In the end, he was just a guy who went around talking to people and having debates. Theoretically, anyone can do that.
Which means anyone can be killed like him.
And that can really strike home for folks.