It is always a temptation to deconstruct literature and in so doing, see it from our modern perspective. Over the years, critics and literary analysts have examined Austen's work for minute clues into her society, her morality, the divergence between her morality and her society's morality, and her psyche. In so doing, the notion has taken root of Jane Austen as a moralist. In her own mind, in her own day, in the minds of her own readers, and in the minds of the contemporary critics like Sir Walter Scott, Jane Austen was not a moralist.
From a contemporaneous viewpoint, Austen wrote novels about a very narrow range of society with a very narrow range of interests and life experiences (Emily Bronte criticized her and her work for just this failing, as Bronte saw it). The contemporaneous viewpoint valued Austen as one who could capture society and its characters with precise detail. She did not preach; she did not expose; she did not moralize. She told of life in her social sphere with exquisite detail.
She was not intentionally a moralist nor a moral philosopher. However, from our vantage point in time, it is possible to extract moral principles, moral issues, moral problems, and moral points of view from the stories as told through her humorous ironic voice that gently unwraps her characters to tenderly, yet ironically, expose their human foolishness and weakness.
So while Austen did not fancy herself as a moralist, and society did not read her as a moralist, her precise understanding of the society she lived in and the people she lived along with allowed her to develop a picture so sharp and clear that the moral issues of her day are revealed through the lens of analysis today. As Sir Walter Scott said, her was not the highest form of genius but it was certainly the rarest form. American Chief Justice John Marshall confirms this analysis by his remark concerning Jane Austen:
Her flights are not lofty, she does not soar on an eagle's wings, but she is pleasing, interesting, equable, yet amusing.