Subjective reality has nothing to do with it.
They know exactly what they are doing. They are sociopaths.
You see, committing a crime or doing some wrong is human. We all do it, to some extent or another, but we usually feel bad about it, or at least, make excuses for it, even if only to ourselves.
But some people feel they have a RIGHT to do these things, even an obligation; that their victims have it coming to them because they are inherently weaker, dumber, immoral, inferior. Fantasies of the Master Race were not confined to the Nazis, and the criterion was not always racial.