PayPal is just a service that moves money between a buyer and a seller. When you send money through them, they're not responsible for checking if the person you're doing business with is honest, that's your job. Anything over $500 and you should use an escrow account.
And like DomainPairs says, there are people getting ripped off from Thiefs. When you think of PayPal, think of Western Union, they only transfer money between people. I have used them for years and they've never bungled any of my transactions.