"Never attribute to malice that which is adequately explained by stupidity."
The simplest explanation is an out-of-touch billionaire who got rich off other people's ideas and spent his life surrounded by yes-men had an idea that he could reverse the course of a declining social media corporation. He boasted about this, and apparently even convinced himself, enough to make a half-hearted (yet legally binding) offer. He then learned he would lose billions if he backed out of the deal.
Those are the facts. The rest is a fine conspiracy theory, but there's just no clear, provable evidence. He hasn't personally benefited in an obvious way, either before the sale, or since. No one can prove the Saudis, Koch Brothers, Trump, or anyone else put him up to it.
Though I'm totally willing to hear evidence I might have missed...
Twitter is too egalitarian for him and his financiers. And tweaking. ThE AgOrIThM for political gain was too much temptation for his financiers.
Mastodon was just the spanner that could be the downfall of their Evil Plan. Zuck tried to detail Mastodon with Threads, but that is going nowhere too, especially in the EU.
Government: "You must do the responsible thing!"
Billionaire: "I'll just move my business to some other country."
Government: "Noooo!"
How things work for Elon Musk:
Government: "You must do the responsible thing!"
Elon: "Fine, I'll make it so that this service isn't available on your entire continent."
Government: "..."
Elon: "You were supposed to go 'Noooo!'"
Govenment: "..."
Elon: "Not having access to Twitter is a bad thing, isn't it?"
Government: "..."
Elon: "Guys?"
Government: "...Just go, it's not like anyone cares about the damn thing."
AFAIK, the name is from back when Reddit still had a positive view of the guy. The subreddit was created as a counter to all the posts painting him in a good light. Nowadays I don't see the point of this community anymore though.