So, I'm not so sure that the baby/dog to encampment dweller connection makes the most appropriate vehicle for mentally dealing with the poop. Or, maybe, it is the right vehicle. I really don't know.
When I rationalize my poop scooping duties by juxtaposing them with the duties of parents and dog owners, I end up placing the babies, dogs, and adult poopers in the same category. I don't know if that categorization actually reflects reality, and therefore I can't tell if that kind of rationalization will actually help me react to the poop in a constructive way.
If I, as an adult, can clean up your poop for you, then it escapes me why you, homeless but also adult, can't pick it up and put it in a dumpster. The logical conclusion is that you do not wish to.