I think ignorant might be more accurate than stupid. That crosses into stupidity if the ignorance is wilful eg they refuse to accept facts or refuse to even investigate if someone tries to present evidence.

People these days seem exhausted and angry and for some there’s comfort in the ‘certainty’ of their wrong beliefs. I read a piece recently about an ex qanon guy who said a large part of the appeal was being part of a community and encouraged to be angry about everything.