Don't get me wrong.  I definitely think abortion is a very bad thing, but I think what Keillor is saying here is that there is more than one way to respond to evil and that some responses are more effective than others.  If what you care about is the welfare of children, then getting involved in a child's life is much more likely to have a practical positive effect than a symbolic, generic condemnation of abortion.  The condemnation is cheap in the personal investment it requires compared to the act of service.

The pro-lifers who demonstrate at Planned Parenthood clinics and hold up pictures of bloody fetuses should rather hold up signs with the number of hours per week they're volunteering for child care, and then we'd take them more seriously.

That's a quote from p. 111 of Homegrown Democrat: A Few Plain Thoughts From the Heart of America by Garrison Keillor.  I read it during our get-away trip to the UP.  Get yourself a copy or ask to borrow mine.