Could be he's that low in IQ but I don't read him that way.
His meanness and vileness have a certain . . . complexity, diversity, robustness for all their unidimensionality.
I think someone with a low IQ would have had that aspect screaming from every word and phrase. I don't see that flavor in his stuff. Could be wrong.
Yes, a low IQ screams at me. A more subtle and insidious troll would not have done what he did.
Regards, Ivan