Because he used his money to turn a townsquare into truthsocial 2.0 and now is paying trolls to stoke division. He is not a good actor.
PS: just to be more explicit: there are amoral people who screw you over without even noticing it, that's how the game was set up, ok. But that is not what Elon is doing. This guy went out of his fucking way and took a loss to ruin a platform for everyone. Think about that. Imagine going out of your way to hurt yourself so you can hurt others more. And this guy says he wants to manage a Mars colony and lead humanity into the future. Please, Jesus, no.