They do this to get closer to their real goal - zero abortion rights. This is just one of those things without a happy compromise because you disagree on the core value. At best an uneasy truce, and tables will flip whenever there is a power change.
I don't have a better solution but I think it is unwise to continue fronting the legal/consti fight using child/rape/medical cases as the key points. They have never been swayed by it but we keep using them as trump cards expecting something to change. I don't know if anyone is getting the same vibe but their responses over the years esp on the child front seem increasingly dismissive and hostile.