That's a weird take. The shopping part is provided to you for free for your convenience. Not returning the shopping cart means you are creating a nuisance for other people who are coming to the store to get the things that they need. It is blocking parking spots, potentially going to damage somebody's car, and no longer in a centralized location.
Not returning it is inconsiderate in multiple ways.
Nah, yours is the dumb take. I guess returning your 3D glasses at the end of a movie is too much "unpaid labor" for you. How about cleaning up your table at a restaurant that doesn't have servers? I guess you just leave the mess sitting there huh?