There has been a convergence of many factors, but I think in short, the abandonment of, and rebellion against traditional Judeo-Christian morality has left a vacuum filled by moral relativism. The inevitable result of this is that each person becomes a "god," unto themselves.
Evaluating the ethics or moral virtue of a situation, person or decision becomes much easier when the standard by which one judges is, "because I said so." Moral relativism is intellectual laziness, and without the strictures of moral absolutes, society will, like raging floodwaters, seek the path of least resistance, and destroy much of what is in its path.
