While you're correct that he owns Twitter and can do what he wants with it, your analogy doesn't work. Nobody else uses your Toyota and the colour provides no functionality. Twitter has been the platform for breaking news and political discussion for years now.

A better version of your analogy would be if you replaced the exhaust on your Toyota with one that pumped out visible smog. You let people hire it for a drive, as you did before. But they drive around our homes.

Originally, we could say "You can't drive here anymore!" but now you let them drive anywhere regardless. Oh, and some of these drivers now play Hitler speeches through the sound system while they do donuts on our driveways.