I have to disagree. That just absolves this guy of repsonsibility.
The sad truth is, we humans do not need anyone to control us and make us commit horrible acts.
Exactly.
There's more than enough fuel for the moral fire - fallen mankind is involved in the same rebellion against God as Satan and his fallen angels (demons). Sometimes the evil one provides a spark, though.
Humans will spend eternity somewhere - either in God's presence or outside of God's presence with Satan and his followers.
I don't think demonic possession absolves the possessed from responsibility. There is the subjugation of the will to the evil spirit.
Nevertheless, I think you may have a point and that is we cannot give in to describing this act as anything that shifts blame away from the perpetrator. When I use the term "demonic possession" it is very vague and conjures, most likely, many different meanings. Sorry for any confusion and I think your point is sharp and valid.