In other words, it doesn’t matter whether abortion is murder or not as long as the person who hires the killer thinks it isn’t.  Using that looney logic, the Ku Klux Klan should be allowed to legally kill black people as long as they claim to honestly believe that black people are not really human beings. 

Obviously, we cannot allow individuals to create their own realities in order to justify killing other people.  In the case of abortion, if woman “A” believes it’s murder and woman “B” believes it’s just a choice, it is not possible for both of them to be right.