As a metal devotee, I suspect the number of people on this site who enjoy black metal which purports to be Satanic is extremely low. The sweeping generalizations made in this thread seem quite out of whack with my experience on this site and in the metal world.
That said, I certainly will not listen to any bands that spout any anti-Christian garbage. For my Christian friends (none of them Catholic) who do, many of them would say that they listen to metal for the instrumentation, not the lyrics, and they could care less what the lyrics are saying: Christian, Satanic, or anything in-between. And let’s be honest, you can’t understand the lyrics of most black metal bands anyway
They also would contend that for most of those bands is it 100% gimmick and not something that the band believes at all. This reasoning doesn’t satisfy me at all, but it seems to suffice for many.
And like someone said, not even all black metal bands are Satanic. There are Christian metal bands in the genre: I am familiar with Crimson Moonlight, Crimson Thorn, and Frost Like Ashes.
I also have a Christian concert promoter friend who promotes black metal concerts (among many types of metal). I have asked him this question, as it does disturb me that he does so. He sees himself as being Christian outreach to these people. The people involved in Satanic black metal (and that actually believe it) have an intense hatred for Christians, feeling them to be evil hypocrites. In a music business where bands get screwed by everyone - especially concert promoters - my friend is honest, fair, and treats the bands exceptionally well. His goal is that these anti-Christian guys will have to reconcile this thought “This guy is the only promoter that treats us well, yet he’s Christian, which contradicts everything we believe about Christians”.