Software (and I guess hardware too) is about tradeoffs. The tradeoff here is that in not being able to validate if a device is a valid Airtag is that Apple has created a massive, completely uncontrollable surveillance network. The fact that anyone can interrogate the network to track devices that aren't even guaranteed to be running the official firmware or have the official hardware is insane. Not having Apple be able to know the location of the tags is pretty much irrelevant in the face of this downside.