Not allowing secret manipulation by the deep state, corrupt states, or removal of speech that doesn't cater to extremist sensitivities.

It's the reason for the entire news post we're all commenting on.

When Elon first bought Twitter, they released a bunch of information on how governments (specifically the US government) was pressuring Twitter to remove content, often for political reasons (i.e. it was a conservative account, etc). He stopped doing that, and generally supports free speech on the platform; sort of in a 2008 reddit way