“Wrong life cannot be lived rightly.” – Theodor W. Adorno 
Ethics as a philosophical or ideological subject is both social and individual. Its purview is the regulation of individual behavior under an assumed social context. It may also involve a critique of the social context in so far as reality does not live up to ideals. But the ideals are as a rule predicated on existing social reality even when critical of it.
Marx’s & Engels’ dictum that in class society the ruling ideas are the ideas of the ruling class holds here. The virtue ethics of an Aristotle or Confucius presupposes and justifies the repressive institutions of the existing order. Presumably some concepts of use may be extracted from them, but only selectively, shorn of their metaphysical and sociopolitical obfuscations.
In bourgeois society ethics undergoes certain transformations. Kant is a superb example of an individualistic ethics which both criticizes pragmatic social reality and reflects the presuppositions of emerging bourgeois society. Self-submission to an abstract concept of duty, irrespective of circumstance or inclination, the illusion that one can actually live as if others could be regarded as ends and not used as means, as if this were an individual matter, represents the quintessence of bourgeois illusion, of fairness and strict accounting in the marketplace, even as it criticizes the actual by reference to the ideal.
We could go through the various systems of ethics and unearth the tacit assumptions behind each—utilitarianism or any ethical calculus being the most obvious correlate to the quantifying tendencies of the capitalist marketplace and the money economy.
Ethics at this historical stage goes hand in hand with the secularization of society. What about ethics postulated as the basis of a movement or institutionalized philosophy? Here the secularization of religion comes into play.
Consider the Ethical Culture movement initiated by Felix Adler. Adler, raised in the rabbinical tradition, was philosophically a Neo-Kantian and politically a social reformer. If we move ahead to the forging of the first Humanist Manifesto of 1933, we see also an inclination towards social reform as well as the secularization of religion: the Unitarian influence in the formation of this humanist movement was considerable.  We have here, as in other instances, a transition from theology to philosophy and a liberalization of religion to the point of jettisoning its supernaturalist baggage.
In the ensuing decades we have seen episodic issuings of new manifestoes, publication of books enunciating the principles of humanism & delineating secular ethics, endless regurgitation of the same generalities, with varying specifics in laundry lists of social concerns.  The abstract principles of liberal democracy and individual human rights have been laid claims to along a spectrum of political positions, from libertarianism to anti-Stalinist Marxism.  To the extent that abstract humanistic principles serve as rallying points to focus attention and forge coalitions in differing social situations, they may be useful, though hardly resulting in a full-fledged sociopolitical world view as is often claimed.
Once one speaks of creating a new ethical system to be formulated and promulgated as a doctrine, especially as general principles have been enunciated time and time again and are already part and parcel of the moral arsenal of liberal democratic values, we see how little advance has been made in the past two centuries to transcend idealistic metaphysics. Whether it is individual ethics or a planetary ethic, what could be more pointless and ineffectual in the absence of a serious social movement that provides a comprehensive social analysis and platform?  For all the prating about the scientific method and scientific morality, a secular ethics is pure ideology, a metaphysical massage for the upper middle class intelligentsia and assorted entrepreneurs, a superimposition of a schema of platitudes onto social reality concomitant with a numbing of any serious analysis of class society, and absent serious linkage to reform movements in the manner of the mid-19th to mid-20th centuries.
Ethics as a new religion or religion-substitute had its time as a stage in the liberalization of religion and the reforming instincts of a “liberal class”, useful up to a point even with its limitations. But what it represents is long obsolete, actually retrograde by comparison with today’s needs and apparently progressive only with respect to right-wing religious revanchism. Religious humanism apes the institutional structures and moralistic sermonizing practices of its supernaturalist forbears. Secular humanism forgoes religious humanism’s obvious mimicking of religiosity (albeit in attenuated, watered-down forms), but preserves the ideological ornamentation of middle-class respectability: “we’re nice people and we have an ethical catechism to prove it.” Such earnest naïveté has lost its charm. 
 From Minima Moralia (1951). See also Wikipedia entry and Lambert Zuidervaart, Review of Deborah Cook (ed.), Theodor Adorno: Key Concepts. The standard translation by E.F.N. Jephcott is available in hard copy. Another translation can be found online: Minima Moralia, translation by Dennis Redmond (2005).
 Edwin H. Wilson, The Genesis of a Humanist Manifesto.
 See my bibliography, Secular Humanism—Ideology, Philosophy, Politics, History: Bibliography in Progress.
 See for example Tolerance and Revolution: A Marxist-non-Marxist Humanist Dialogue, edited by Paul Kurtz and Svetozar Stojanovic (1970) and Humanist Ethics: Dialogue on Basics, edited by Morris B. Storer (1980).
 Paul Kurtz still adheres to a social liberal, social democratic perspective and his condition of manifestoitis is chronic. See Humanist Manifesto 2000: A Call for a New Planetary Humanism and Neo-Humanist Statement of Secular Principles and Values: Personal, Progressive, and Planetary (2010).
 The ideological limitations of humanism were criticized by anti-Stalinist Marxists a half century ago and more. I have blogged twice about George Novack (William F. Warde, pseud.), “Socialism and Humanism” (1959) and Paul Mattick, “Humanism and Socialism” (1965), criticizing both. Mattick’s application to this post is more diffuse. Novack never updated his analysis from the 1930s, when Trotskyism and the liberal humanist movement were serious ideological contenders and competitors. Neither Novack nor Mattick seriously address the need for specific secularist campaigns and coalition politics even in their time, a lapse now especially obvious in the absence of the left wing working class movements of yesteryear.