I completely agree with the overall point you’re making, but would like to correct the legal aspects. I am not a lawyer, but I do have a pretty good understanding of US copyright law which is the most relevant in this case.

Having possession of data isn’t sufficient to legally establish the rights to do as a company pleases. In general, an individual author immediately has copyright on a creative work as soon as it’s recorded in any medium. The main exception to this is “work for hire” — a legal agreement that employers hold copyrights since they’re paying for the work. It’s usually part of the paperwork an established company has you sign when you start a job.

Because of this, and because we users aren’t employees of Reddit, they need a license to duplicate and display our copyrighted posts. The terms of service for any online service almost always stipulate a “worldwide, non-exclusive, perpetual license”. In other words: you still own the copyright to your post and can still share it elsewhere, but by sending it to Reddit, they get to put it anywhere they want and you can’t ever take that right away from them.

If Meta begins slurping up data from the Fediverse, things get tricky. They’re probably violating copyright law if they do that, just as ChatGPT, Google Bard, etc… likely have. However, legal enforcement of our rights would be near-impossible. Everyone who has ever had an account with any of Meta’s properties has most likely agreed to an binding arbitration provision. (These are utterly immoral, they force you — as a precondition of doing business! — to preemptively waive your legal rights before anything occurs that would cause you to need them.) These provisions also prohibit any sort of class action, so each individual person would have to initiate their own case against Meta. And then you’d have to somehow prove to an arbitrator from an organization selected by and paid by Meta that Meta violated your copyright. And Meta’s high-priced lawyers will have all kinds of ways of referencing prior cases to argue why what they did is fine.

So yeah. But again, I completely agree with your main point. Meta will (if they haven’t already) collect all the data they please from the Fediverse and use it to further their business interests. And those business interests are not aligned with our best interests.