Playing devil’s advocate, perhaps the level of risk associated with allowing low-level (or even senior manager-level) support staff to transfer ownership of accounts is too high? The level of sophistication of scammers/hackers/fraudsters is likely well above what Facebook would likely employ as support staff. They likely would need to staff paranoid paralegals to ensure customer support doesn’t become yet another luc…
Yes, the only semi-secure way to do account resets is in person and courts are one way to do that.
For requests of account ownership transfer or resets, I would say this is probably the best way to go about it, as it basically prevents people operating in other countries from having a chance at taking over your account remotely by playing customer service reps, and greatly raises the barrier in general for any fraudulent activity happening in the process.