Yes. Being out in any weather taking care of something because other people are too lazy to do so is humiliating. I have no idea why you think it isn't.

And are they really getting paid fairly? If I looked up the pay of someone who returns carts, would it be a comparable wage to someone sitting in an office all day despite it being a much more physically demanding job?

Because otherwise, I think you and I have very different definitions of "fairly."