It’s a tough question for sure and I don’t think there’s a clear answer. We can start by refusing to support the worst of it, calling out the friends and artists who do, and making it seem less normal and acceptable than it really is. Black metal has become such a safe space for it. Even the term “NSBM” helps whitewash it!
Edit: I'm not trying to insult or shame you for using "NSBM." Everyone says it, it's totally normal at this point, and that's the problem.