You are correct, and it is Amazon itself who trained the buyers do just that. Prior to RFS, 3rd party sellers did their own refunding when the item arriver back.

RFS put a stop to that and allows buyers to scam and defraud sellers by the hundred every day. See if you can find out what the Amazon Buyer Violation Prevention Team does. A very highly paid team that sits in an office and says nothing about how they are preventing buyer violations, like you stated.