The anti-abortion position needs to be looked at in the context of eugenics, https://courses.lumenlearning.com/culturalanthropology/chapt...
That it really took off in the 1960s+ isn’t surprising with Nazi death camps fresh in everyone’s mind, leaving a very bad impression with anything tied to eugenics and its proponents.
While I don’t agree that abortion is equivalent to eugenics—-sorry, if my wife were to die otherwise I’d choose abortion—much of the revulsion has its moral roots in the argument against eugenics.
As far as I know that case isn't even considered abortion by any mainstream pro-life organization.
I was surprised they didn't mention this case until I realized it didn't even count in their view.
Some pro lifers want zero exceptions, but it’s extremist.
If you look at the extreme countercultures of the 60s, you see one side who hated "the system" that produced mass affluence, but loved the fruits of it. The other side loved the system, but hated the fruits. So one way to look at it is as a sort of political shibboleth indicating that you were definitely on one side and not the other.
[1] https://books.google.com/books?id=cf5RFWIMJugC&pg=PA42&lpg=P...
[2] https://en.wikipedia.org/wiki/Francis_Schaeffer