Once again let me expound on my favorite theory:

The metality under discussion is what I label as “neo-humanist”. People who have given up on ever perfecting us incorrigibles but who have declared themselves perfected.

Thus they do not view themselves as a higher class of person but as a superior form of being. Therefore they do not think they are bound by the constraints that bind all human beings. Completely amoral, they are drawn to muderous regimes like a moth to flame. That is because those regimes vigorously repress
any and all dissenting viewpoints.

It is not that they ignore those rivers of blood, or even excuse them as temporary abberrations; they positively revel at the prospect of their helping spill all that blood.