Why is it that 99% of those who favor abortion are opposed to the death penalty?
Because those folks are morally confused. They have no problem with killing off the "little piggies," to quote Tereza Kerry. But they realize that, being morally facile, they might find themselves behind the eight-ball in such a criminal conviction and sentencing. Thusly, the life they clamor for might someday be their own.
Obversely, there are those 99% opposed to abortion who also favor the death penalty. Their logic? Criminals deserving of the death penalty had their chance at life and blew it; the aborted unborn never had the chance...(nutshell analysis).
This approach can be expounded on for paragraphs, but you get the idea.
Because it's ok to kill an undefined tissue mass (read baby in the birth canal) because that's innocent life, but it's not ok to kill a murdering scumbag (read potential or probable Democrat voter.)