No, of course it didn't change their mind. But I don't do it for the True Believer™. I do it for the person on the fence who sees these interactions.

Yes, it is a terrible thing to say because it's not the adult antivaxxer that gets hurt in those situation. It's the kids, and they don't have a say in the matter. And, trust me, I've seen parents cry in agony over a deformed child from Congenital Rubella Syndrome, and months later they claimed they wouldn't have done anything differently.