They had records of my folks purchasing the laptop, but they argued that state ID's and credit cards can be faked and stolen, and were thus inadequate for their internal security purposes.
And so you can still use the computer just not keep your data.
Those cards are easily forged and there is nothing you can realistically do to prove the laptop is yours without also allowing thieves/criminals to prove it's theirs. And so they have to err on the side of caution.
The onus lies on you to keep backups.
Also, Apple eventually unlocked the laptop.
In this case you are wanting to keep the data as well.
They certainly turn to Apple for help, but I think it's sometimes simply despair and not flipping their shit.
E.g. I was once in an Apple store and the Genius was trying to help someone who, for some inexplicable reason, did everything in the Guest account of her laptop.
The laptop rebooted for some reason (maybe she said OK to install updates?), and she lost the contents of Guest. Which means she lost everything.
Vendors like Apple need to be prepared for all sorts of data loss scenarios. Ordinary users simply don't think about computers the same way as engineers do.
Regardless of the reasoning, if you have this ability, you can and will be compelled to give up that information. Therefore, it is best to not have that information or STFU about being concerned about privacy.
Whenever someone loses their account the first thing they do is run to the vendor and flip their shit when the vendor is unable to do anything.
I imagine from a business perspective it’s just better to keep access to data, sometimes without nefarious reasons like advertising, rather just keeping customers happy.