You’re not looking at this correctly. No one congratulates themselves for returning the cart.
The point here is that the simple act of returning the shopping cart is the baseline of ethical behavior. This is just illustrating that society’s individualism is so strong that this simple act of spending 10 seconds to keep the place in order is often ignored.
Of course people that return the shopping cart can be ignorant assholes as well. But the point is that this extremely basic act is severely lacking in society. Therefore we can’t expect, as you said, more advanced ethical values. Such as using one’s time and energy to promote changes to other foreign countries