She wasn’t upset about the pictures of abortion—I’m sure she thinks those are lovely and heartwarming.
She was complaining about a photo of a black man being lynched. The pro-lifers were equating the two, saying all genocide and mass violence are wrong.
I think they know that the two are equivalent and don’t want to face up to the fact that they are condoning something that is the equivalent of something they know is universally condemned.
In other words, the truth about their belief system makes them mad.