Creating a system where buyers can extort and outright steal from you with little recourse and no mechanism for warning others of their behavior was a GREAT idea. I should be able to neg a guy for buying my item and not paying for it so that his identical item at a higher price could sell. I should be able to neg someone for a chargeback after the item's been delivered. I should be able to neg someone for trying to return their damaged item in place of the good working item I sent.
They've created an environment where the buyer has nothing to lose from bad behavior.