Thanks for the note.
I've read Ostling's book (and thought it was pretty well done), but haven't read Krakauer's. Despite being interested in the Daybell case, my real interests are not connected to extremist religious groups/violence, and so I can't claim any special expertise on this.
I've been reluctant to get into the Krakauer book partly because some (though not all) who read the book seem to take away the message that there's something about Mormonism that's uniquely prone to violent extremism. I prefer your position, and think there's plenty of backing for it historically and sociologically. That is, virtually any religion -- indeed any almost any complex system of thought, whether religious or non-religious -- can lead people to countenance and sometimes become involved with unspeakable horrors.
But it is true that each system of thought creates its own pathways that are useful to understand in specific situations.