It made a deep impression on me to witness a person who would use his religion to try to make random women who saw that sticker feel guilt and remorse over making a very difficult personal choice. To me that was all about trying to shame vulnerable women he happened to come across, and making them doubt their own decision-making powers, robbing them of their integrity. He probably felt like a bigger, better person for displaying that sticker.
And robbing them of their peace of mind. Basically it was a below the belt emotional punch. You're exactly right, Mikaela, that's exactly what that bumper sticker's message was. The driver probably not only felt self-righteous about that bumper sticker, he - and it was likely a he - was all about showing women their "place" - at the mercy of a shame culture.