It's certainly possible that he has a high IQ, but you can't really judge someone's cognitive ability based on what they post on the internet.
I'm a good example of that. I can write like someone with an average(ish) IQ online because I have unlimited time to think about how to articulate my thoughts and construct them into coherent sentences, use a spellchecker, and look up words I don't know. Take all of those advantages away and it's VERY obvious that I have a low IQ. In real life it's apparent to everyone that I'm dumb as fuck. Some people even think I'm pretending to be stupid for comedic effect because my level of stupidity is shocking to them.