Sure but this is like 0.2% of the overall shareholders in most cases, particularly with large companies like HBO/Max or Disney. Or 2% at the outside. The rest are owned by companies/institutions and people - and mainly the former - who are solely interested in how much money they're going to make on this.
So that's a long post to talk about a situation that whilst true, is completely irrelevant to the realities of the situation and, with respect, basically amounts to #notallshareholders.
Musk is a poor example because he's now so rich he's beyond any normal sane behaviour, and as you note, earlier attempts to manipulate stocks in ways that, were he less rich, might well have ended in criminal sanctions. So he was clearly out for the money on some level. Since becoming super-divorced he and getting the strange brain rot that afflicts some divorced-and-very-online men* (something even he realized in a moment of lucidity a while back) he also frequently accidentally damages his own stocks with own entirely needless behaviour and is well on the way to becoming a completely mask-off far-right anti-semite. He was pushing and promoting anti-semitic conspiracy theories in public only a couple of days ago, not for the first or even fifth time. That's not something someone whose brain works properly and who likes the companies he's involved with would do. Even if they were so irrational and paranoid as to believe such theories, they'd keep them to themselves - hell even Ford, who was a lunatic conspiracist issued a public retraction and apology for The International Jew (though his underlings had to forge his signature on it). But this is a guy so wealthy, if he lost literally 99.9% of his wealth, he'd still have hundreds of millions. Most people, even wealthy people, would be put straight into poverty if they lost 99.9% of their wealth. Thus because there are essentially no personal consequences for his actions, they're driven by whimsy and delusional beliefs. I think I preferred the stock manipulation and edgy teenager behaviour of his earlier years.
* = Something slightly similar afflicted Rowling, I note - basically self-imposed social isolation from peers (in part due to wealth) combined with being surrounded by lickspittles with extremist beliefs that she was already predisposed to believe.