Unless I'm misunderstanding, a big point of contention is activation lock specifically. Unless you're buying $50-100 iPhone 7's and 8's off marketplace, chances are tons of devices you see in landfills are activation locked phones that either had their battery cut out, got cracked to the point where the user couldn't use the device, or were so badly damaged they just threw it away with no thought to reuse. In this case the iPhone(/iPad/Mac) is still locked, but enabling scrapyards to repurpose them by disabling activation lock would either allow criminals to do this as well, or if you had some vetting process to be able to remove the lock, it might just then the scrapyards de-facto dumps for stolen iPhones (since the scrapyards will like pay more for each phone once they can repurpose and sell them).