Yes they are entitled and we are allowed to disagree with it. That's the point everyone is trying to make. These legalistic arguments are silly and distracting.
I do feel most of this whole issue could be sidestepped with some long overdue antitrust enforcement.
Yes this is the reason. They will continue to stifle speech so its more palatable for corporations to run ads on their platform. Censoring art and dissent is working well for the people you agree with right now. 60 years ago the current culture would have been unfathomable. In 60 years it may be unfathomable to you again, but now you've taken the stand that it's right and just that they stifle dissent. Hope that never bites you.