It is if you know about the ability. If he had kept silent about it, then assuming a player didn't know there action were redirected then he could try using it in a Scummy way.
Chopbam is basically claiming a suicidal ability that can easily be tested also since it'll redirect actions to him.
Which is decisively the opposite of what Mafia want to do in this game.
Generally, the assumption is if we start pushing a case on a Mafia member, then the other member has to either make a case against a different person or make a case for no-lynch to keep the suspected Mafia member alive.