I agree with you for the most part, but you omitted the symbiotic (or even mutualistic) relationship users and platforms have. For example, Google provides a video platform, and user provide the videos. Such a transaction comes with a contract we all neglected to read, but accepted regardless. As far as the contract is concerned, both parties should be fine with this situation. Nobody is stealing anything.

Obviously, this situation has quite a few problems, and the Fediverse addresses many of them. However, self hosting text, audio and video doesn’t happen for free, just like Google can’t run their servers for free. Either you pay directly to the devs and admins, or you find other creative ways to make money flow. That’s where the Fediverse and commercial platforms differ greatly.