Ok I am missing something.
If the accident was caused by an unsecured ballast bag then the pilot is at fault.
If the accident was caused by the skid being caught, on trying to lift the pilot felt that the skid was caught but carried on / had been so aggressive with the lift they could not stop - why is that not the pilot's fault?
Never landed on these pads, but had a skid "stick" in muddy conditions many times. Unless you are attempting to jerk the aircraft into the air, which is pretty foolhardy, why would you not lower the collective when you felt the skid was stuck?