Personally, I think that a partial repayment would be reasonable even if Goat can afford the whole thing. The contract says "best effort", and the money probably was really lost and not just pocketed by Goat. Goat was apparently investing almost entirely in Pirate or other funds investing in Pirate at the time.
Nope, goat was "investing"
other people's bitcoins in pirate, and pocketing a fee. Regardless, if he wasted his own money with pirate too (which I doubt), that is not Gurrty's problem, no more than its Goat's problem how Gurrty lost his entire fortune.
Anyway I have a suggestion for you. The list of VIP's that donated 50BTC to this forum reads almost like a "who's who" of bitcoin scammers. zhoutong, pirateat40, Graet, imsaguy, TradeFortress, cryptoxchange.. Why dont you do your part, and refund Goat's 50BTC to Gurrty, and strip Goat of his VIP privileges? At least it would be some small restitution to Gurrty, it would show you do not want to be paid with stolen money and scammers can not buy protection from you with their stolen money, and if Goat wants to regain his VIP status, let him cough up the coins himself.