Musk bought it because he's a dumbass.
Because he thinks he's clever and wants everybody to think he's clever (also because he was mad that Twitter kept banning his buddies for being fascists), he hatched a plan to send Twitter a formal offer to buy it for way more than it was worth. Musk thought that Twitter was owned by a bunch of left-wing ideologues and were using the site as their own personal microphone (sound familiar?), so when they inevitably turn down his offer, he could go "Aha! Gotcha, you fuckin' Marxists!" and everyone would clap and call him smart.
But Twitter was not owned by a bunch of left-wingers. It was owned by businessmen. Musk's buddies were getting banned because it's not good business to have an advert for Disneyland next to a racist/anti-Semetic tweet, not because of ideology. And when those businessmen saw that Musk was offering to buy Twitter for several times what it was worth, they jumped on the offer, then sued Musk when he tried to back out.
Hilariously, Musk agreed to buy Twitter as soon as the discovery process started. I'd bet money that his phone was a black hole of cringe/illegal activity and he wanted to keep it from going public.
Musk didn't want to buy Twitter, and he doesn't want to destroy Twitter; it's just a side effect of using it to stroke his ego.
Too late. Their parents got to them first.