He said, specifically, people who already have it firmly established in their belief system that abortion is child murder will almost entirely be unswayed by data showing that the current bans aren't effective enough at preventing abortion. They only see it as meaning "the current bans aren't strict enough, and in order to prevent child murder, there needs to be a full nationwide ban".

These people aren't just uneducated on biology and human reproduction (even though that applies to most of them). They for the most part understand that a fetus isn't actually a person in the way a newborn/child is. But that doesn't affect them because the belief is entirely emotional, not scientific – people have a fundamental, irrational moral belief that an unviable fetus is worth more than a living human being. How exactly do you prove that a fetus isn't part of their vague and subjective concept of what a "person" is, if they already won't take biological and psychological evidence as proof? And, following that, do you expect to be able to convince someone that child murder (in their eyes) isn't bad?

I get your reasoning that surrounding them with people who believe actually rational things, and who refuse to tolerate irrational beliefs like "abortion is child murder", will pressure them to also start accepting those things, but that misses the point of what the person you're replying to said. He said that data like the one in the post won't change their mind – and, imo, it still applies when considering how it might affect the beliefs of others since it's not a matter of effectiveness, rather a matter of emotion; a fundamental belief that parents and doctors who go through with abortions are child murderers and bad people. Mature people are just bound to eventually realize that abortion isn't at all even close to comparable to murder, if they have basic knowledge of reproductive biology, and immature people are bound to stick with whatever beliefs they had since they were a child, most often anti-choice in a conservative society.

It's something that changes peoples' minds on drugs, but not abortion. One of the most common insane things is conservative people going to a clinic to get an abortion (or get their kid an abortion), the same people who take part in and sometimes even organize the protests against places that offer abortion services, and get the abortion all while insulting the other people in the clinic and saying how they're evil people who should be ashamed of themselves. They literally can't see the hypocrisy in it, they have an ever-present belief that they're the exception, that their abortion is the only moral abortion. Even when you confront them with the fact that many of the other people getting abortions have similar or the same reasons, they just have this innate visceral reaction to the fact that you're comparing them (or their actions) to her (or her actions). Out of the dozens of cases of this I've heard of, only like 2 of them had someone that changed their mind eventually. And this is the absolute most extreme scenario that one could see an anti-choicer being confronted with in order to change their mind.