If you had actually read the article you'd see it said it's NOT TRUE. That it's just pattern matching and no such thing is happening.
Second, it was comparing pro-Islam audio showing up in unexpected places just like people used to claim the same about Satanism. (eg play some music backwards and you hear pro-Satan lyrics) It was not comparing the two subjects or saying that Islam = Satanism.
Third, Satanism isn't what most people think. The Church of Satan, arguably the largest group of so-called Satanists, is actually atheistic. Its members don't believe in the supernatural, Christian or Islamic.