Again, and I can't believe I have to say this apparently, the word "stupid" is not ableist (and just because someone gets frustrated with you when you say it is doesn't make you right or good either, that's literally fashist troll logic). The word means "marked by or resulting from unreasoned thinking or acting." It's not about someone's inherent capabilities or arbitrary IQ it's about them forgetting, refusing, or being incapable (which is because of a lack of self awareness and critical thinking skills, *not* a disability) of carefully and critically examining what they're saying or doing. It's A) something any and all of us can fall into, perhaps especially those considered "intelligent" because those people are all the more capable of rationalization and overconfidence and B) a really useful word to describe this kind of systemic personal lack of thought or analysis for whatever reason, which happens a lot, and needs to be called out when it does.
@LunaLupus got blocked by another person named Luna for being a "chronically online hot take spewing fake anarchist" for saying this so its funny hearing it the other way 'round LMAO