Morality is not exclusively deontic. There are, after all, many things that are morally good to do though not required, or morally bad though not forbidden. However, a deontic conception has gotten a grip on the contemporary conception of interpersonal morality, or morality insofar as it has to do with proper relations between persons in virtue of their personality. One presently popular conception of interpersonal morality runs along these lines: Interpersonal morality consists in obligations or duties that are incumbent on all persons; to have a duty is to be accountable to somebody. If I am accountable to somebody, then she has standing or authority to demand my compliance; and to exercise this authority is to be disposed to respond to noncompliance with Strawsonian reactive attitudes and practices expressive of them.
In the last chapter of my book, How We Hope, I identified a common interpersonal attitude that eludes deontic characterization: disappointment in a person, or feeling let down by a person. I proposed that holding people to demands is only one mode of interpersonal relation, and that placing hope in people is another. Demanding involves a disposition to the central Strawsonian reactive attitudes of resentment, indignation, and guilt (and perhaps contempt and shame, which I will come in a bit); placing hope involves a disposition to disappointment (and perhaps some positive interpersonal feelings like gratitude and admiration, which I will also come to later).