“Just about all murders of innocents could be committed using this same rationale.”
No, all murders of innocents do not have the context of the rape and incest against the innocent female.
It is not an argumnent for an open-ended gneral case, or a slipprry slope to it, but just two very specific special exceptions to the general case.
I was speaking of your previous qualification that abortion could be justified because the babies would probably go to heaven. That was the rationale that could be applied to ALL murders. Just because a murder is committed under extreme or even criminal circumstances does not make it acceptable to compound the crime by slaughtering an innocent, defenseless human being with the rationale that the victim will probably go to heaven.