Speculation. You could be completely wrong. So could I. I think to do something such as this, your brain has to be hard wired for hate. There is no shortage of obscure causes to attach yourself to. People will hate you because your are:
Fortunately most of the people that I know and most of the people you know as well as the huge majority of American’s think this abhorrent. So causes such as these get no traction.
My personal opinion is that this type of hate is either demonic or biological. Normal minds don’t function this way. But as I said. I could be wrong. Let’s see what the shrinks have to say.