If you took time to look at the photograph, you'll notice the tops on some are unscrewed, safe to say the seller is complying with the conditions of sale.
They dont have to be used to be second hand. Just by virtue of the original purchaser selling the item makes it second hand just so long as they are not listed as new. Thats where bargains can be had.
So you buy goods from a warehouse and sell them here on a forum that says the goods have to be second hand..by your theory everything is second hand as shops have to buy from manufacturers
This site makes it quite clear that it is not for retailers to sell their goods and the items must not be marked as new but it does not state that they must be used. You start going into the murky world of health & hygiene with some items if they were previously used. I feel you have made you point, as have I;it is a grey area to try to put exact definitions. It is more down to intent.