PayPal is no more crooked than any other consumer-oriented banking business. They do offer pretty good protection for buyers (but only in some specific circumstances) and their protection for sellers is extremely limited (and in some cases actually works against the sellers).
On eBay, I purchased a "new" monitor that turned out to be used. PayPal made it extremely easy for me by escrowing the payment until we renegotiated. The seller thought that his monitor was as good as new (it wasn't) and probably ended up feeling like he got screwed.
If anything, PayPal greatly misrepresents the benefits of their Buyer/Seller protection and, considering that they are actually part of eBay, grossly overcharge for eBay payments.