At this point, I agree the pot should be split.
If you deal a board using cards that have been mucked, you can theoretically win/lose the hand thanks to cards that ought not to be in play.
I'm amazed anybody would agree with the ruling other than for karma
Every card that has been taken out of play is still an unknown, the odds for the 2 players that are still in the hand doesn't change when the others players hole cards get dealt back in to the deck. The deck gets shuffled and a new board gets played out seems like one of the most trivially correct rulings ever.