They do this because they either were born or have been tortured into being a psychopath. And they have bought the "big lie" that there is no life after death. This is the biggest lie they buy that allows them to do the evil shit they do. They have bought into the "life is a dream" retardation.
Without empathy they need to do a lot of thinking thinking thinking to see their mistake. But a mistake they are making is for sure.
A big fucking mistake.