And who would enforce such a right if we have no governmental oversight?
If they did, they'd be breaking their own value prop of a place to share things, which by definition means people need to be able to get at it easily.
Facebook's value proposition is people sharing things within the platform. You can perfectly well provide that service and at the same time make it hard for users to migrate their data to a different platform. They already did it in the past. [1]
Again, this stinks of non-customers trying to interfere with Facebook customers for dubious reasons out of fear.
Indeed. In this case, the non-customers are Facebook's users and I believe the fear of entirely justified.
[1] https://www.cnet.com/news/facebook-blocks-contact-exporting-...
That's not how it works.
You have rights and easy access to your data - always have. 3rd parties don't get my PII unless I let them. Heck, I can download a ZIP file of everything I've ever uploaded with a single click! It makes zero sense they would prevent you from getting at it, if they did, they'd be breaking their own value prop of a place to share things, which by definition means people need to be able to get at it easily.
Again, this stinks of non-customers trying to interfere with Facebook customers for dubious reasons out of fear.