How did Phillipe Pinel’s view of mental illness support the idea of moral treatment?

The Moral Treatment Movement (1800–1850)
The moral treatment movement was introduced in the United States by mental health workers who either had studied or had visited Europe where they became acquainted with moral treatment principles. However, unlike Pinel's version of the moral treatment movement, which made no reference to religious morality, in the United States it was a unique “fusion of enlightenment philosophy with American protestant piety” (p. 2),40 modeled along the principles used at the York Retreat. Chief among those who spearheaded introduction of the moral treatment movement in the United States were Benjamin Rush, Dorothea Lynde Dix, Thomas Scattergood, and Thomas Story Kirkbride.
Benjamin Rush was a physician and also Surgeon General of the Continental Armies.47 He is also recognized today as the father of American psychiatry. He was well acquainted with enlightenment philosophy and moral treatment ideas. He was remarkably influential in American politics having signed the Declaration of Independence.38 Consistent with moral treatment principles, Rush “made the first systematic effort to classify patients and improve their behavior through recreation and humane discipline” (p. 3).8
Rush indicated his disdain for cruel treatment of the mentally ill by his concern for the “slender and inadequate means that have been employed for ameliorating the condition of mad people” and his dissatisfaction with the “slow progress of humanity in its efforts to relieve them” and the tendency for them to be treated “like criminals, or shunned like beasts of prey” (p. 1).47 He set out to reform these conditions for the mentally ill. As a result, Rush led an effort to construct the earliest hospital in the United States to be devoted exclusively to the humane treatment of the insane