In religion’s defense, many religions are also being used to prop up pro-choice. It just so happens 2 or 3 of the largest religions are very outspoken so the rest of them are getting ignored.
Stealing from Pew, almost all of Judaism, Universalism, and many of the major non-evangelical protestant religions are pro-choice. Even Islam is largely “limited pro-choice”. If I had to guess, the majority of religions weighted by adherents are either morally pro-abortion-rights, or at least pro-choice due to lack of mandate otherwise.
…if we look back at the US Civil War, the Christian churches fell on both sides of the Slavery argument fairly consistently, basically based on what their constituents wanted to hear.
I mean, with asterisks? The Catholics only get away with that because they reject Sola Scriptura, and sometimes treat some of the words of their Church Fathers as “the next best thing”. Even then, they’ve gone back and forth on abortion (and largely treated it as a minor issue) until only the last few centuries.
…but along those lines, I’ve never really seen a Catholic argument against abortion try to lean too heavily on Biblical sources. Because they know they’d lose.