Kim C's last post summed it up very well indeed for me.

"Understanding" of this kind of thing from the outside is never going to be fully possible. You can't make sense of it because it doesn't make sense. You can tiptoe round it and try to get a greater understanding, but in terms of the sort of motives and reasons we have to do things in normal life it just doesn't add up.

The analogy that makes some sense to me is the way you can have a dream and it all seems to make sense, but you in which you aren't in control, you are present, but as a kind of passenger. A nightmare.