With the religious background I had, I can see this as not being trolling. I even had a similar experience myself (although not related to heavy metal music). I have come to notice that within Christian mythology there exists this idea that you can sell your soul or whatever your hear desires. However, outside of the blues, children's cartoons, and Christianity, this idea hardly exists. But within fundamental Christianity there exists the idea that you can literally sell your soul to the devil for anything you want. This (fundamental Christianity) also tends to come with a very high level of paranoia, such as how we see with the so-called "war on Christmas" or how "secular America" is "waging a war" against Christians. They literally and fully believe the world is out to get them (it's why I'm not a fan of Richard Dawkins, because I have seen how his words, and the words of others like him, become a cheap source of fuel to instill and deepen fundamentalist's beliefs, especially in regards to anti-science propaganda. It's still a bit early to call this user a troll, but even if that is the case the mentality represented in the OP is something that is very much alive, very real, and the seeds are sown, fertilized, and nurtured by a fundamentalist approach towards Christianity - those who cannot see the forest for the trees.