Just like folks that are anti abortion and pro death penalty.
Superficially quite similar, but substantively different. More babies are aborted than criminals are executed in a given year. The exchange of souls is skewed against the innocent unborn.
Being against the death penalty and pro abortion is defending to indefensibles. The first being the protection of a convicted murderer from a duly legislated, and authorized execution after conviction beyond a reasonable doubt; and the second being the condemning to death of a human being for which the mother can choose to not be responsible for and thus give it up for adoption.
An adult that commits a capital crime is given multiple opportunities to appeal their punishment. Many have their sentence commuted to a life sentence. Such criminals are given time, opportunity, the means, and more time still to deal with their fate. The unborn child has no appeals process, is given no time, and has the means for life cruelly snatched away for no good reason except that it is not wanted by an unknown parent.