There was a time that feelings, perception and reality matched closely. This allowed for a fairly common cognitive model, which translates to a relatively uniform morality. With the advance of science, and the interaction of diverse cultures, the cognitive model is more diverse and subtle. An example (from science), is that most of us have a cognitive model which includes a concept of bacterial disease. In addition, cognitive biases have been introduced based on the diversity of culture and technology. All of this can lead to cognitive dissonance, in some cases, unless the moral basis changes with time. Recently, the Church has rejected moral relativism, but for the past 2,000 years it has embraced it. This is a radical change, which is probably a reaction to the increasing rate of change which it struggles to adapt to as an institution.