Do you know their rating? Tbh most people’s idea of being “pretty good at chess” is actually not very good at all (I don’t mean that as an insult, more lack of familiarity with the game).

That’s not to say that it’s impossible for someone to think those things and be a strong chess player, but it’s probably not super common. I’ve actually ran into a couple people at a local chess club with “interesting” ideas about vaccines and uh… let’s just say they were not hard to beat (I think I mated one guy in like 12 moves). And btw, I’m not even a super strong chess player myself (~1134 USCF). But like, they probably would seem really strong to someone that just occasionally plays chess at family gatherings or whatnot. Chess is a game with a low skill floor and very high skill ceiling, so you have a huge range in ability.