Some people value the testimony of those who are willing to publicly say they have had an abortion and they regret it:

While walking from work to the metro I stopped off infront of the Supreme Court to hear a group of women speak. The women all held signs stating "I regret my abortion" and one by one they got up to a podium and spent about 10 minutes telling their stories. Many broke out in tears as they told heart-wrenching stories of their youthful mistakes.

To see first hand people who actually had experienced such a life changing event was amazing. It did something to me no statistic or article could ever do.

And some people do not appreciate this public witness:

And speaking of abortion being murder, there are a bunch of ladies in the pro-life rally being held today who have signs stating “I regret my abortion”. They now want abortion to be illegal. So, by their own logic, they should be in jail for murder. Do you think any of them are going to volunteer to go to jail if Roe v Wade is effectively overturned? No fucking way.

And:

We just returned from the Supreme Court and I'm feeling blue -the Planned Parenthood, NARAL and NOW supporters had all left by the time we arrived and most of the people still there were holding 'prayer vigils' and waving signs like "Everyone deserves a birthday" and "I regret my abortion."...

...The "Women need love, not abortions," posters were really outlandish - as Brian aptly remarked "No, women got love, now they need abortions." Also, the "I regret my abortion" poster holders angered me. Yes, women are forced to make tough choices when faced with an unplanned pregnancies, and sometimes they regret those choices (whether they chose to keep, abort, or give up for adoption) - however, just because some women now regret having had abortions does not mean abortion should be inaccessible to those who need and want them! It's an incredibly selfish kind of logic - I had an abortion, then I felt bad, so nobody else should be allowed to have them.

And:

Of course all the republicans were on stage reading their talking points and at the end they would proclaim they were Pro-Life. While standing in front of women holding signs saying "I regret my abortion." I wonder how many of them actually had abortions?

All of them, honey. All of them.