I don't know how people are making these authenticity arguments using NFTs, because your counter-argument is spot on. Having said that, the anti-counterfeiting mechanism for physical goods like Birkin bags is exactly the use case for Vechain.
Because people are desperately investing reasons to justify themselves because:
1) they're gullible and bought into the hype, or
2) they're shady and want to make money off of the gullible.