Hi, Angela - I agree about the shoulds. If someone is shoulding on someone about their shoulding on other people, they're doing the very thing they think people shouldn't do.
Sacred duty made me think of something different than moral obligation. Moral obligation being: you "should" do this, and if you don't you're somehow bad or wrong.
Maybe it would be better to think of it as Sacred calling. As in, something a person is inspired to do.
Again, I'm still not sure what the OP really meant about this. But everyone seemed to think she was talking about other people. My first thought was that she was talking about it for herself. She said it's a phrase that resonated with her. I didn't get the sense that she was trying to make anyone else do anything. Maybe I'm wrong here.
Regarding that last paragraph "If your really want to be effective in getting the result that people born in richness/and or happiness are making a greater effort ...", I don't know if that was directed at me or not. I'm not trying to get anyone to do that.