From M.o.1 -- Interesting thing with Satanic imagery is that there are different forms of Satanism. Some of it is hardcore violence however there is another side of it which is very much just a focus on the self as the primary concern along with developing power. Having studied both sides in the past, I tend to find that most talk of "satanic evil" tends to more from the outside user making assumptions about what they are viewing rather than what is actually happening. Much of what people believe to be "Satanic" are actually something else not any less evil but not performed to the deity Satan.
However, make no mistake about it, there ARE EVIL people out there who are doing such rituals! The thing that ends up happening though is that many of these people are kind of "useful idiots" to those who are controlling them from the top of their particular cult. Groups like "The Order of the Nine Angles" are said to be very violent in regards to human beings but other orders such as people who follow LaVeyan Satanism are more about tapping into the animal side however they are appalled by blood sacrafice.
It's an interesting system to look into as far as understanding what some thing actual are as opposed to what people believe they are.