If we always come to the same incorrect conclusions about the reasons people did some horrible things, we'll never stop horrible things happening now and in the future, it seems to me. You could be right about what was going on in the head of the guy who burned the building, but also could be wrong.

The source of what I was commenting on below (I don't know how else to link to it), has an interesting view of the mindset behind another recent horrible event:

https://eric-bott.medium.com/scary-but-real-insight-thanks-for-that-ed8609b8e62c