I get this all the time. Too often I'll even get someone trying to pick a fight with me, but if they actually read my post they would find I agree with them. Either that or they'll bring up a point I already addressed in my post.
There's a certain point where if I feel someone's not comprehending what I'm writing, continuing the conversation is a waste of my time. Even insulting them would require literacy on their end.
Some of the earliest studies I read about COVID was how it can enter the brain like meningitis and effect a person's cognitive functions. This was a while back and I can't vouch for the accuracy of the information, but seeing how much people have seemed to have lost their minds over the last few years makes me think back to that study.
I can't say I've been immune to it either. I have never been "symptomatic", but the last 3 years have definitely felt more hazy than the times before, and have made me question my own sanity.