People have already explained that it is about safety.

As for your analysis, I'm afraid that it is uncomplete. You would need the break down by age. I mean, many pro-forced-birth women are religious (virgin until marriage as an ideal), married and/or old. So those pro-forced-birthers women aren't having sex with pro-forced-birthers men. They might be married to one and having sex with that man, but not the others.

So a better way to stimate if they would notice would be dating apps. Specific dating apps for right wing people have a way higher ratio of men compared to women. Conservative men complain about progressive women not giving them a chance. They also complain about not getting enough sex and have joined a movement called "Incels" to precisely complain about not getting sex.

So I would say that they already have noticed progresive women not wanting to date them even before that. It wasn't intentional, just progresive women disliking right wing men for their values, but it already has been noticed. Didn't worked to change their minds though. But still makes perfect sense, as people usually want to date and have sex with people sith similar values and that they like.

As for your "fix", while pro-choice men can have sex with pro-forced-birthers, chances are that those women want to marry and have children. Many don't use contraception. I don't think you really have think this through.

And conservative men lie about being pro-choice to get their way. Some also tamper with contraception (which is the reason women might chose to not have sex).

Then there are people who are born from conservatives, but grow up to be progressives. I know, shocking, right? Conservatives have this idea that they children would grow up to follow the same religion and live the way they are told. Then reality happens, and many women decide at the middle of their lives that no, actually they don't want to live like that. Cue divorce. But if people have always the same values as their parents, we would still have the same values as when we became homosapiens.

So avoiding sex with conservative men is about avoiding unwanted pregnancies that would be forced to carry to term, not about changing their politics.