the twisted thinking of abortion

Abortion doctor and activist Henry Morgentaler admitted on his website (http://www.morgentaler.ca/new.htm) that the unborn are in fact people by referring to them as "children:"

"Most of the serial killers were neglected and abused children, deprived of love. Both Hitler and Stalin were cruelly beaten by their fathers and carried so much hate in their hearts that when they attained power they caused millions of people to die without remorse. It is accepted wisdom that prevention is better than a cure. To prevent the birth of unwanted children by family planning, birth control and abortion is preventative medicine, preventing psychiatry and prevention of violent crime."

My question to Morgentaler is this: if judging who is undesirable before they're even born is acceptable, then why not kill them after their born and legalize infanticide? By trying to prevent another Hitler, isn't he just promoting the same thing that Hitler did, which is to decided who should live and who should die?