it's because his personal social media feed is clearly infested with conspiracy and white supremacist extreme right QANON garbage. He's been steadily sinking down that hole for several years now, and it's been very evident by the stuff he's been tweeting, and who he's been liking, retweeting, and responding to for the last several years.
It's formed an established and very worrying pattern that i've been monitoring (and raising red flags about) for some time. Five years ago he was a "moderate libertarian" joking about Spaceballs and Monty Python. Unfortunately, he's been swallowed whole by the absolute dregs of the extreme right, and his jokes are much more likely to be, say, transphobic or defending a guy who attempted to murder a Democrat.
It's the biggest, most credible risk to Tesla's share price, but over in the investment thread, the mods hate hearing anything that's not mindless cheerleading, so they shunt it out of sight as soon as they see it.
not being able to talk about Tesla's share price in the Investment Thread is the most ludicrous example of this site's inept moderation.