This is actually a thing I've experienced. The dog has been dead for 4 years. Obviously, I'm friends with my dog, so it reminds me of her birthday (couple days ago) and then I remember that this account exists and they won't let me delete it. I tried to report her as deceased and it wanted an obituary.
That's what I tried to do, and that's when it said to submit evidence. I was like, "uh, the evidence is that I was there when it happened and you can see from the profile that it's for a DOG," and they said that wasn't good enough. I just gave up. Her profile will outlast all of us, probably.
If the account is obviously active it's pretty unlikely that they're deceased. It wouldn't take a lot of vetting. Although that probably is about 50 times more work than they would bother to put into it, so maybe you have a point.
That customer support has always been teetering between abysmal and non-existent. Even back in the olden days when Facebook wasn't too bad it was still pretty much awful customer service. It's just not something they've ever really bothered about.
My cousin's Facebook page is still up and he's been dead for over 10 years.
They were being really weird about it because it took ages to get a death certificate, because he just disappeared one day, so we had to wait for the authorities to decide that yeah he's probably dead, but we just don't know where. I think in the end his parents just gave up with it rather than trying to deal with Facebook.
Why do people put up with a platform like this? Their customer service is practically non-existent when you need it, but is is still able to muster up energy to demand obituaries, driver's licenses, etc?
Maybe you could email them a vet record instead? The vet can print out her vaccines and the computer will put a deceased label on it if shes marked as deceased. Vet records are technically legal documentation so they may qualify