Many decks just don't have viable counterplay against cliffdancer . It is literally a low risk - high reward play that doesn't require any kind of skill (it's just based on maprng as already mentioned) & this kind of gamemechanic is just unhealthy.
In addition to that pure fire was already very strong against many decks, so it's not like the deck was cliffdancer-reliant. The strategy just created the opportunity to win games without playing better than your opponent, which makes it really frustrating to play against.