I don't see where it says Terry or Keyes were actually pushing carriages. Can you show me where it says that?
I have no idea what the controversy is (imagery is important in any message), however, there is an image posted above and Keyes was pushing one. He was right on the front line.
See the photo above, and also Terry said “we.” That makes both of them. By the way, what makes you think Terry and Keyes would lead their pro-life supporters in pushing the carriages but not push one themselves? Do you see them as chickens?