I don't think that these days there's anyone out there who puts much past what religious fanatics will do.
Really I don't mean to disparage religion, or belief in God. I have to acknowledge that I don't share either view. I'm not an atheist, but I'm agnostic in the sense that it's going to take more than anecdotal tales for me to overcome my skepticism and reach a level of faith that is by definition not contingent on rational thought processes. Even then, I still think based on historical data that organized religion is a creation of people rather than some artifact of divine intervention. Whatever its origins, though, pretty clearly structured religion has a remarkably strong grip on the minds of many, and can lead its adherents down some pretty bizarre, and not infrequently violent, paths; those who profess great belief in the teachings of Jesus, or Mohammed, or Buddha, and so on-none of whom preached a reliance on force as a means of spreading their word-seem to find a resort to torture and slaughter as their chosen means of compelling others to believe and act as they do.
Thus, I think my shooter in this chapter is a very realistic creation. A sad reflection of the human condition, to be sure, but both in the past and today it's all too frequently to be found in the very much non-fictional world in which we live.