The US has limits on free speech in the name of public health and safety. There's no assumption of limitless free speech in the US. People who cry "free speech" typically have no understanding of its actual legal definition in the country and just want an excuse to be a bigoted asshole without consequences.
Twitter, not being part of the government, gets to decide what content they allow and doesn't need to worry too much about the legal definition of free speech. But, despite Musk's claims, Twitter is not actually a space of limitless free speech. They've taken plenty of actions since he took over that limit the speech of individuals he disagrees with. Twitter is just interesting in giving a platform to hate. There's certainly money to be made in monetizing hate (see Trump), but hopefully it doesn't work out well in the end for Twitter or Musk.
Seriously. My Nissan Leaf in Eco mode (which limits acceleration) feels peppy and is super fun to drive.