“To return the shopping cart is an easy, convenient task and one which we all recognize as the correct, appropriate thing to do.”
The flaw here is that anyone can take issue with this statement and say “I don’t recognize it as the correct, appropriate thing to do. Stores hire cart wranglers to manage stray carts, and if everyone returned their carts, those folks would be out of a job and their families would starve”.
By sneaking an unsupported assumption into the problem, the creator left it wide open for that sort of chicanery.
I’ve never heard of full-time cart jockies anyway. They have lots of other duties. And the hypothetical concern about losing their jobs in kind of like “broken window fallacy” in reverse.