They just rationalize it and say that they're doing things for the right reasons. And then, because they're broken, because there are things missing in their brains that normal people have, they sleep soundly at night.
The irony is that you assume a normality which is just not there. The norm is to be broken in the way you describe it.
It is not about the things missing in your brain, it is about the things added to it. Prejudices and 'common sense' allow for a good nights rest while doing horrendous things. That is the norm, it is like humans work, that is how trump, sexism, racism. anti-semitism, etc works … ironically that list includes advertising too. ;-)
And now am in a bad mood, I would rather talk about the glory of the empire. Real People are messed up