Everyone agrees that abortion is a Bad Thing, so no-one is “pro-abortion” – at least I’d thought until I researched current usage. There are enough usages to be noticeable. Most of them are part of “pro-abortion rights” or “pro-abortion-rights” (which is awkward however it’s hyphenated) and “I’m not pro-abortion; I’m pro-choice”, but Google’s first page of results includes “pro-abortion Christians” and “pro-abortion protesters”. But those are those writers’ description of other people, not those other people’s self-description. Another result is the Cambridge Dictionary, which defines it as “supporting the belief that women should have the right to have an abortion” (my emphasis).
Equally, everyone agrees that life and choice are Good Things, but equally “anti-life” and “anti-choice” are used. The first seems to be a distraction, because most of Google’s results are references to the Anti-Life Equation in DC comics, which I didn’t know about previously and won’t pretend to understand. But I can easily imagine some people in the current debate referring to other people as “anti-life”. (And no-one is “pro-death”, either. In my state of Australia, the current debate is about voluntary assisted dying.) “Anti-choice” seems to be the most used, but similarly by some people about other people.
I’m going to stick my neck out and say that no-one self-describes as “pro-abortion”, “anti-life” or “anti-choice”.
“anti-” relates variably with nouns that follow. Google Ngrams’ top 10 results are Semitism, corruption, slavery, poverty, trust, Christian, climax, Catholic, chamber (a mistake for ante-chamber) and freeze. Notable here are -Semitism, -trust and -climax. Semitism doesn’t seem to be a thing; Google took me straight to anti-Semitism. (Compare, in earlier times, Zionism (rather than pro-Zionism) and anti-Zionism.) Trust is a Good Thing, so being anti-trust is surely a bad thing. But the term refers to the use of corporate trusts in certain bad ways. A climax is a good thing, but an anti-climax isn’t against that; it either doesn’t happen at all or happens to lesser degree than anticipated.
Note that being anti-something doesn’t necessarily mean being pro-the-opposite or even pro-anything-else. Anti-government protesters probably aren’t pro-anarchy (though some may be); they are either pro-some-other-group-being-the-government or pro-a-change-in-the-system-of-government. And anti-freeze does not mean pro-boil.
On the other hand, Ngrams’ top results for “pro-” are slavery, cess, duction, tection, vide, vision, visions, portion, ceedings and fession, which means that there’s something wrong with either their programming or the way I’m using their search terms. I was surprised at the use of pro-slavery. I hope that no-one is pro-slavery these days.
Note: this post is about language usage. Any comments otherwise will be deleted.