It's not an intelligence thing (yes, he's not a genius but that's not to say he's not very intelligent and has some deep technical knowledge in some areas) - I think the thing is that Musk has generally demonstrated poor judgement and low ethics in many areas (think Solar City acquisition, tweets leading to SEC legal action, Thai cave diver slur, some of the cryptocurrency stuff, now this whole Twitter thing, etc.).

People expect intelligence to lead to good judgement but I'm more and more convinced that (assuming a decent baseline of intelligence) they're fairly separate and unconnected things.