It's extremely easy to believe that there exist people who would, given the chance, kill Trump. There are plenty of people who think he's literally Hitler, and who wouldn't go back in time to take out Hitler in the mid 1930s if they could? When you convince yourself that someone is dangerous enough, you can convince yourself what you're doing is a good thing.

The only thing I find surprising is it took this long for someone to have a serious pop at him. And make no mistake, I believe USA came half an inch from civil war starting. I do believe that a successful assassination of Trump would cause serious breakdown in security in USA.