Well ironically in a homogeneous society, and one with a clear sensei of purpose, they would be right to do that, because you can't maintain a society without reinforcing its expectations.

If I throw litter on the ground and someone says 'we don't do that here, pick that up'', that's actually fine as far as I'm concerned (and most other people I'm guessing).

The question is, where do you draw that line? Is it wearing / not wearing the right sort of hat in public? There has to be a line or you don't have a society at all.