You go to the park, you see a kid littering, you tell them to pick up their trash. They tell you to mind your own business, and make YOU feel bad about talking to a child who isn't your own.
The problem with the duty system you mentioned is it needs a lot of buy-in. It's like it's metastable, it works when there's buy-in, but generally it doesn't work. As soon as someone is willing to question it, it falls down. "Who are you to point your finger" is surprisingly effective at reflecting shame.
In the mid-20th century we were still at the height of nationalism. People thought to be English meant you had to do certain things, believe certain authorities. During that century, people started to notice the cracks and it all went.