My point is that these people are quite logical and rational, based on their moral(?) code in what they do. Their code says that it is good to kill innocents and infidels and if they die too, that's good too. So it's quite rational for them to do the things they do.
The solution is: 1. You either have to deprogram them, or 2. You have to kill them. I don't #1 will work very well.
# 2 would be my choice, then.