A fair point. However, my argument remains the same: we have decided to exclude certain things, such as abortion and self-defense, from the definition of "murder."
Legally, yes. Though "we" is a bit vague. Self-defense as a valid excuse comes to us through common law and several millennia of Christian experience.
Abortion came as a proclamation from a court. And it is still very much in dispute.
The Court seemed to have erred in jumping ahead of the consensus, which has had very bad effects on politicising the judiciary and polarizing politics.
SD