It’s a play on the classic riddle:
You’re walking on the beach with your good friend Jesus, huffing paint and dissociating. At one point you forget what you were doing and look over at Jesus, then back behind you at the sand. Behind you there’s only one set of footprints. You ask Jesus why he left you and he looks directly at the you who is reading this, not the you who is in the story, and asks “Why do you think there’s only one set of footprints?”