I used to see threads like this on reddit where people would defend the act by claiming it keeps people employed. Anyone who has worked in retail knows otherwise, but it doesn't stop these neanderthals from existing and making their bullshit toxic arguments.
And knowing how corporate works in these sorts of places, they ain't gonna hire/roster more people to deal with the extra work, just push the existing staff even harder so they don't have to pay out extra hours.
The worst shit is when I see someone dumping a cart, they see me, smile and nod at me and then walk off like they haven't just been caught being shitty.
Imagine if that's how the world worked. Help your toilet cleaners by shitting on the floor and smearing it up the walls. Litter pickers looking like they need the overtime? Just tip the bins over.
As far as I'm aware, that is the case for some of the crews at different stores. Mainly the ones based in larger malls or shopping centres that have their carts spread out over a large area. Those are the ones you would see using the ride-on vehicle with the trolley trailer hitched.
For the most part though, at least here in Aus, the trolley collectors are also responsible for cleaning the stores.
Places I worked when I was younger, it was just one of the jobs of the courtesy clerks, along with bagging and filling some things to the shelf. Even in a really busy store, I think there'd be a ton of wasted time if someone was doing only carts.