Remember, those rights are rights that the GOVERNMENT cannot infringe upon. If the government were to say to Twitter that they can't determine who is part of their platform, that would actually be against Twitter's first amendment right.
Free speech on platforms owned by private parties is NOT a right we have.
Twitter, Facebook, YouTube, Google are private companies. We have no more a right to free speech in them then you do at any other business. THEY have a First Amendment right to prevent your speech.
Either the government operates it's own Twitter, Facebook, YouTube, Google,s or decentralized platforms that cannot be controlled by a single point are the real answer.
But an IBOR would help until these platforms are built and ready to scale to the size of these huge services.