Religion is a poor source of morality

[Esquilax]

Seems to me that people do not always agree on basic material facts of history, crime scenes, and even scientific findings. But few people would say that obectivity is impossible in those areas. To say that for morality to be objective the facts must be incontrovertible strains the definition of objectivity. Why should anyone assume that moral knowledge cannot be objective just because people lack full understanding of the area of inquiry?

There's an important difference though: in terms of history, scientific findings and so on, there are at least actual, objective things that can be pointed to. Scientific findings, for example, are the result of experiments that take objectively real things and manipulate them in certain ways to isolate variables and causes. But when we come to morality, there is no demonstrable or detectable thing that those claiming objective morality are able to show at all, merely the demand that their morality is, in fact, objectively correct.

In other areas of potential objectivity there are at least things that one can refer back to to support the claim of objectivity. What references of that type exist for the claim of objective morality, aside from books filled with claims and fiat assertions?