A woman's body belongs to her. In my opinion, it is just as wrong to force a woman to give birth to a child she does not wish to give birth to as it is to force a woman to abort a child that she wants.
Women (and men) are entitled to their opinions and to making choices for themselves in line with those opinions. In my view, though, they are not entitled to control another woman's body and life by forcing her to have a child she does not wish to have.
We already have thousands of children in care homes and foster homes, with a significant proportion of those children experiencing emotional difficulties and mental health issues in adult life. Why not concentrate on children such as these who are already here? But that would require far more commitment of energy, time and money than carrying posters around and harassing women when they are at their most vulnerable.