In my opinion... (I am not a judge).
If the totem is a Stoneclaw Totem next to the attacker, the proper way to do this is to go
"This is an illegal attack, you have to attack a Taunter."
The attack couldn't be declared so it's not binding. Like if you tried to move a Rook diagonal in chess.
If it was a Grounding Totem next to the defender (with a magic attack), or a Protector, then you go
"Alright, attack targetting my X, I'll redirect to Grounding Totem/Protector."
At this point there's no turning back as the attack was already declared, and the redirect is an effect that follows from the attack, not something that made the attack illegal.
"The beatings will continue until morale has improved."
- Standard corporate management technique