I see criticisms that all seem reasonable (as in, you can certainly disagree with them, but they are not baseless petty attacks), but I see very little (if any?) ad-hominem.
Nah is plain envy, professional envy, none of those "non baseless petty attacks" comes from people that can say they worked in the most disruptive tech of the new century.
Or he's a jerk. I don't know either way but there do seem to be at least two possibilities. A third is he's a jerk in real life and people are envious of some of his accomplishments. Hard to say, so I try to reserve judgement.