Neglect of spiritual hygiene turns communities into hotbeds of moral disease wanting quarantine. We do not call for immediate physical quarantine of persons who sin, for reasons already given. However, there are psychic and social forms of quarantine, and these forms of coercion can be utilized to induce people who show no regard for the wellbeing of the community, and it can be done without radically disrupting their lives. In traditional cultures this was common. To socially ostracize a person who promotes a lifestyle that is generally considered immoral is a way of psychically quarantining them so that their influence is minimized, and so that physical removal does not have to occur.
At any rate, the underlying principle is that moral education is a public duty, not in the sense that the public authority ought to be responsible for conducting it in its structure and method, but in the sense that it is a duty imposed on all individuals by the fact of their participation in society; and this is in addition to the private duty for self-education, the latter being facilitated primarily by the traditional religions. But do not be confused: the latter does not replace the former.