I think your only fooling yourself Kwok, if you think Paypal is to blame for what happened to you. Paypal has many safeguards in place to prevent hacking and Phish attacks, could they be more secure? maybe, were they negligent? I doubt it, this is a separate issue for the court to decide, just because the account was hacked into, doesn't mean Paypal should let you have the money, that's just nonsense, I'm NOT a fan of Paypal, but if you understand how the chargeback system works, Paypal did exactly what they were supposed to do, your gripe should not be with Paypal, if your going to point fingers, point them in the direction of Visa/Mastercard or whatever card was used, there the ones in control here.
And BTW, Paypal does protect sellers, they provided you with $5000 in seller protection coverage, but you completely ignored Paypals warnings of selling intangible (digital) items, disqualifying you for the protection. Losing your domains to a crook is tough to take, but aside from Bakhtaran, I think you share the majority of responsibility.