Yeah, they're role is ostensibly in preventing most forms of censorship, and championing the notion that the way to curb shitty speech is with more speech. NOT by silencing things which run contrary to our sacred cows and favorite icons
In The US, The Constitution explicitly entrusts the government to uphold our civil liberties, free speech included. THAT'S why it's incumbent upon us citizens to hold our civic leaders accountable for doing so
I think you might be misinterpreting "free speech". Twitter can delete all of your tweets that say "Musk sucks", and that is absolutely none of the government's business. It's not their job to try to convince Twitter otherwise. That's not what free speech is about.