you cant call it a society......., a society is where people live together,they live happily,they care for each other, they understand and respect the feelings of one another.
but here is nothing sort of like that,..........
here we are told to mind our own business,and its not a society
As I said, probably the best explanation is that it's simply nihilistic. It doesn't have an intended meaning, but it's supposed to make you think. That's what the Joker did in 'The Dark Knight' - he can certainly be seen as a nihilist. He uses this quote during the opening sequence of the film in such a way.