A private business can run itself how it wants. Twitter does not have to be free to all sides. Not if Twitter management does not want it that way. Twitter has every right as a private business to be one sided. Hell, they already are. So is Facebook.
Oh, that's right, you want the Government to step in and force Twitter, a private business, to be free to all sides.
If you want Twitter to not delete any posts, to not ban anyone, do something about it. Boycott Twitter. Write letters to Twitter. Maybe if Twitter lost users do to their policies, they may change.
But, do not expect the Government to force a private business to do this. The Government needs to stay out of it completely. Let the free market decide how Twitter operates.
You want a platform free to all sides? Create one.