I read the whole thread, and then decided to sample the music. I didn't let my wife know the source of the music; I just let her listen to get her reaction. When she heard it, she responded, "You know I don't like satanic music." Personally, the music triggered my anxiety, and I had to calm down for a while before coming back to post this.
If there is a message to be gotten by this excerpt, it is ONLY through the music. The words were completely and totally unintelligible. And I read the lyrics before I listened to it. The OP even said that the words couldn't be understood through the first playthrough, but only with repeated listening. This means that the axiom stated before, "The medium is the message" holds 100% true in this case. Because the lyrics cannot (by the OPs own admission) be understood without repeated listening. This means that, until you listen to it enough to understand it, you are getting ONLY the message from the music, which is hate, violence, and anger. You can't tell what that hate, violence, and anger are directed to. You can only know that it is about those.
Those of you who know me will know that this next sentence I do not say lightly. That music made me want to kill. Now, with my background, the hatred it caused to surge into me was directed towards Al-Qaeda, ISIS, the Taliban, and so on. But we are not called to hate these people. We are called to love them.
To me, that was one of the most ungodly things I have heard in a very long time. To me, saying something along the lines of "at least someone is using a medium to reach people who won't listen to other mediums" is like saying, "I am a Christian prostitute. I sell my body for money, but I give them the gospel. These whoremongers might not hear the gospel any other way." That sounds harsh, I know. But I mean it sincerely. There are just some media that cannot be reconciled to a gospel message. And I believe that this is one of them.
I'm sorry but this was pretty funny to read. As the "OP", I said that as you listen to this music more, you understand it better. Not just this song, but once you're used to the sound of the general genre, you understand it after that.
Honestly if your wife thinks music is satanic just because of the type of music, well...then that's just rooted in ignorance of the music industry.
The words, well, they aren't "completely and totally unintelligible", and there's a whole base of this music that would disagree with you.
Honestly if you are able to be turned on to "Wanting to kill", just by listening to a song..then..I don't know what to say. I mean it's just funny that you think this.
Do you think the growling vocals are demonic? Probably, based on your post. Let me ask you a question. Have you ever heard a demon? No, you haven't.
Now let me ask you another question. What do you think of when you think of death metal and its culture? Satanic, evil, putrid, right? I'd like to point out that Metal is one of the least popular genres of music ever, which is why you don't hear this stuff in commercials. Now, if Satan(who has the voice of an angel of light), and who is the ruler of this world, wanted to deceive the most people with his satanic message, what do you think he would use as his platform? Well of course, the most popular genre of music/entertainment that there is...Pop. So. Satan is the great deceiver. He's convinced the population that music like Katy Perry and Taylor Swift is innocent, and that anything that "sounds scary" and is dark, is satanic. I argue that it is exactly the opposite. Take a long, hard look at the Pop artists of today. You will see their music RIDDLED with satanic and luciferian imagery. On the other hand, this song speaks the truth of the Bible(literally straight up verses), but "sounds scary", and for some reason, people like you are tricked into believing it...
Here's a rule of thumb for you. Anytime you see something popular...whether it be music, or movies, or whatever, run the other direction. Satan is alive, living in this world, and deceiving billions of people every day. Take a good look at what you're allowing to influence your life, and then decide whether or not music is satanic or not, just because it's a scary sound.
For me, I would rather listen to the most abrasive, guttural, scary Christian music that has a holy message, then even consider for a second, listening to some Luciferian garbage that Taylor Swift and Beyonce'(and even some CCM artists, believe it or not), put out.
I can understand death metal fine, but I can't understand rap that well. Vice versa is true as well I guess 
