Seems to me this is a completely reasonable policy. IF eBay adjudicates a complaint in the buyer's favor, the seller is liable for the cost of the sale plus shipping; and that amount can be deducted from the seller's PayPal account. eBay makes it easy for itself to collect the money from the seller, but that's just a wise business practice.
Or could it be that there's something here that I'm not understanding?

-Joe-