In the case of Nazis in regards to the Jews and anyone else in regards to the unborn is they have to view their victims as not human. Then it is easy to justify the killing. That is the precondition to wholesale slaughter.
Exactly. It was the thinking behind the justification of slavery in this country (slaves were counted as 3/5 of a man), were seen as personal property whose owners had total control and who could be killed if the master/owner desired without fear of murder charges. The unborn are seen as the property of the mother who has been given the "right" of life or death over her child. Some proabortion people have gone so far as to describe the fetus as a "parasite" (disgusting!). Anything to dehumanize the person so that they can justify their actions.
Just a mass of tissue.