[_se]

Yes, it is very possible for someone to be smart and an idiot at the same time.

Do you think you're smart? Have you ever done something and said "man, I'm an idiot"? It's just like that.

Of course, the other explanation is that he's just grifting, which is also very possible.

[kentm]

"Smart" is something you do, not something you are. People with very large amounts of raw intelligence fall down some very dumb intellectual rabbit holes that its practically a meme: https://www.smbc-comics.com/comic/2012-03-21

Having raw intelligence doesn't help if you don't apply rigor to your thinking. I suspect that very successful people actually end up falling into habitual mental shortcuts that cause them to promote stupid things at a later time.