How is this not shut down in any form? This is actual insanity.

This sort of thing has been widespread in US fundamentalist Christian circles for a long time. He probably goes (or went) to a church surrounded by people who also believe that.

Normalization of deviance. They've shifted what is considered normal so far out of bounds that they can now pretend this is just fine. So no more fig-leafs. It brought down the Space Shuttle, and it will bring down society if left unchecked.

Why is it any of our business what this guy says in his free time if it's not advocating for violence?

Calling people "harbingers of the antichrist" is tantamount to advocating violence, not to mention slander.

If this guy was some raving lunatic on a corner I wouldn't care. But he's got a country sized megaphone thanks to money and has also bought the government. So it does unfortunately matter that he's an insane christian cretin that wants to see the current form of government destroyed.

Because he made it our business by deliberately making it public.