I don't think he's QAnon. I don't think he believes MOST of the nutjobs that he lets on his show, or even cares what they believe. But he lets a bunch of QAnon people on his show, so a bunch of QAnon people listen to him. And he keeps letting weirdos on his show because that's what his listeners want.
I would agree that the context is entirely different in Asia, his show is mostly harmful to Americans and wouldn't affect other countries much.
I don't have a definitive answer to your first question, but why would we want to limit a sub to FOSS-only discussion? It's a more restrictive designation. By calling the sub "open source" we're keeping it open to software that isn't technically FOSS.