Scott said: "Remember, there is a difference between murder and defensive homicide."
In some instances, you cannot separate the two: in war, for example.
"I want the murderer to be incarcerated until, if ever, rehabilitated. What I do not understand is people who actually support murder in theory."
Well, aside from the "murder as a deterrent" argument, which I believe has been shown to be invalid, proponents of "legal" murder decide, by whatever means, who can or cannot be rehabilitated. If it is decided that they cannot be rehabilitated, they are considered a dispensible detriment to society.
Now, if we had reliable scientific means to determine who or who not can be rehabilitated, this argument would have some merit. But as it is, the decision as to who should die is made primarily on moral, political and economic grounds, e.g., how despicable the crime was and how many criminals we can afford to incarcerate.
However, as Nick suggested, when a superficial value is placed on life, the decision to take it is easily made.