Social media firms face big UK fines if they fail to stop sexist& racist content
theguardian.com
theguardian.com
I know some laws like this only apply to platforms of a certain size though, that may be the case here.
I was curious about Musk's dependencies in China (Tesla Gigafactory/ Chinese Car Market access), and just now learned that Twitter is blocked country-wide there. (but routinely accessed by VPN) So if The CCP in particular threatens Musk to censor Twitter, he can just tell them that's their problem.