First off, sorry to hear about the damage to your truck.
That said, was the golf cart long enough that one set of wheels was riding on the tailgate, or do you think the damage came while loading/unloading the cart? If one set of tires were riding on the gate and that end of the cart was not securely strapped down, at 200+/- lbs, anything (a pothole or bumps in highway) that would cause the cart to bounce might have caused the damage. Regardless, since this golf cart "monster" has damaged your truck twice now, if I were in your shoes, I think I would swap that darned thing off!
