It isn't really absurd though, I don't think. If one genuinely believes abortion is murder, it makes perfect sense for that person to not be pro-choice, the same way the rest of us are against people being allowed to legally kill newborns. Whether that individual person is capable of being pregnant does not actually factor into it at all, it's just a matter of what one believes about how the unborn should be 'considered' (i.e. baby vs. 'clump of cells').

I have no problem with abortion, so I don't agree with pro-lifers, but I am not at all confused by it. The opposition to abortion directly follows from their beliefs about the unborn.

That said, though the two are often conflated, just because someone is pro-choice doesn't necessarily mean they're okay with abortion, they could very well be someone who believes more strongly in the individual's right to choose, than in everyone copying them. I've met a large number of women who are fiercely pro-choice but have said they couldn't bear to abort their own pregnancy, even if it was unwanted.