For Twitter I see nothing bad with being owned by Elon Musk. On the contrary. See The optimistic case for Twitter under Elon Musk.
The case against him buying Twitter has to do with Elon Musk himself, and his focus. He can obviously run several complicated companies at the same time, being CEO of both Tesla and SpaceX and founder of Neuralink and Boring Company. That is not the problem.
The problems lie mostly in the future, but owning Twitter means he will have to deal with many of those problems sooner rather than later.
The background to my thinking is that I believe that Tesla will be an enormous company on a scale that we've never seen before. As I lay out in this text:
There I also bring up three potential threats to Tesla. One of them is this:
Big, dominant companies always draw the attention of politicians and regulators. Elon Musk is already attacked by the likes of Bernie Sanders and Elizabeth Warren just because he is the wealthiest person in the world. But he is poor now compared to what he will be if Tesla becomes as big as I predict. They will want to break Tesla up, bring Musk down and all those fights could slow down and hurt the company.
Add Twitter to the mix and he is immediately an ever-larger target of politicians and regulators. The always funny Aaron Levie summarized it in a tweet.
Fast-forward ten years. Tesla is the world's largest company by far, SpaceX has landed people on Mars and is making tens of billions from satellite internet (also a critical part of free speech), Boring Company is building Hyperloops and making billions from tunnels and Neuralink has started putting chips into brains. Elon Musk is the world's first dollar trillionaire.
Musk will have a lot of incoming fire and many of them he can't ignore. Things that he will have to spend time on. Because of Twitter much of that fire will be incoming in the next few years, rather than in ten years or so. I'm sure he can win a lot of the fights, but it will slow him down and that will affect the super important mission he is on.
Right now, Elon Musk is humanity's MVP. For the long-term survival of our species, nothing is more important than establishing a self-sustaining human civilization on Mars. I don't want Musk to get bogged down in fights with Congress, and get distracted from that and his other important missions.
Free speech is of course not unimportant. On the contrary. It has been crucial for our rapid progress since the democratic revolution. Potentially Twitter could play a major role in free speech for humanity, and maybe it will be worth his time now. I hope so.