The issue with the "sometimes you have to work with bad people in politics" line is that it's not true for the dissident right. The dissident right is outside of the mainstream political system, so there is no set path to power. It's decentralized, and there is no hierarchy, and that means there is no authority forcing Nick Fuentes to associate or disassociate with anyone else. He's only "had to" work with bad people out of convenience, not necessity. He chose of his own free will to associate with everyone who's ever been a part of AF.
It was (and still is) entirely possible for Nick to do what he does without associating with and running defence for pedophiles, but he chooses not to.