The standard line in conservative politics (that abortion is murder) isn't supportable by the text of the Old Testament, which outlines distinct punishments for murder and for inducing a pregnant woman (unsolicited) to abort. Causing an abortion isn't even sin in the Old Testament; it just yields a fine. And it's true that Jesus doesn't explicitly address any of that to supersede or revise it.

The 'valid Catholic reason' for the a doctrine of ensoulment that prohibits abortion is just papal authority. Different popes, saints, and schools within Catholicism have had different beliefs on ensoulment; it's not like the reasoning has been decisive here.

Fucking up other people's lives for the sake of obeying a series of 'infallible' flip-floppers is in fact embarrassing and not respectable.

And even from a religious perspective, criticizing particular sects of Christianity as unmoored from their own sacred texts and traditions with respect to this issue is a perfectly valid line of critique of those sects and their adherents. That's what the GP is essentially doing, informally asking what the rational connection to the sacred texts and tradition even are on this issue. Just because the Catholic church has an answer to that question doesn't mean it's satisfactory.