It is unfair to that team. The reasoning behind (from what I gathered from the other post description) is that the league wanted to avoid imbalance in power where one team dominates all others. A three peat kind of shows an imbalance so although it is unfair to the 3-peat team it does remove the possible imbalance by starting over.seems unfair to the team that was able to build a "dynasty" in a dynasty league.
It was just what that league was concerned with. If all owners know about it and are ok with it it's part of the cost of putting together a great team in that league.