Yup... it's just that inspecting the item also has a cost, which may lead to the item not being profitable to resell anymore, in which case it is destroyed without inspection. Or it's the individual employees who choose to play it safe and prefer to destroy an item rather than risk customer complaints if it get resold in less-than-mint condition.

There are vast numbers of returns from Amazon and all sorts of other companies that are not sold by them again, (whether as new or via their “Amazon Warehouses” discounted price) nor destroyed. These items are sold in bulk by the pallet and semi-load to other companies who can do then triage the products and decide what to do with them. Sometimes they end up back on Amazon, for sale by a third party. One local company auctions items online on their own site for pickup only. Others go onto eBay, etc.