Grudge's utility goes beyond simply Relic and Crypt; it is far more multilateral against problematic equipment (Jitte, Batterskull, and Plating), in addition to creating a diffusion for opponents who would then have to play around it. The whole point of the card is to initiate interaction and reaction from your opponent by forcing them to activate said artifact, which is fine.

Dredge (depending on which variant you're gearing yourself towards) has a variety of ways rebounding through hate, in addition to having tools to fight it. The argument for or against something like Grudge is interchangeable because of how subjective it is. Additionally, Dredge is an incredibly situational archetype, so what might be good in one set of circumstances might not be the best in another.