Religion is a poor source of morality

[TheRocketSurgeon]

Robvalue, why do you privilege empathy in your just-so story about natural selection. What about disgust, contempt, and fear. No doubt our capacity for those also evolved to confer some reproductive advantage. Using your logic I could rationalize moral sentiments I'm sure you would find disturbing. For example, disgust prompts us to avoid behaviors that led to injury and disease. Therefore it is moral to shun the sick and refrain from formication. Members of the tribe that are not inclined by normative desires to reproduce should be held in contempt. Or fear of outsiders protects the gene pool of the tribe therefore strangers, particularly those that appear different should be destroyed.

My point is not that any of the above examples are true but rather that contrary to common AF opinion the pressures of natural selection are at best neutral with respect to the origin of moral values.

We definitely have a strong feeling of "in-group" versus "out-group" (xenophobia, or fear of those who are different), but there are many examples of tribal peoples who're (or usually, were, since we've wiped so many out) still living in a way similar to that of our ancestors who had no problem with "non-reproductive" behaviors of that sort. It is quite possible for a non-reproductive member of a tribe to find a role that is helpful to the overall success of the tribe. Rather than listing examples, I will point you to a term to Google: "third gender".

Our concepts of fear and disgust for those who are radically outside the tribal norm is certainly a competitive advantage, and thus evoluationarily favored, but it is a non-sequitur to suspect that the tribe is automatically going to pick sexual preferences as one of those things to consider as a factor for in-vs-out-group identification.

However, we do tend to find that in a particular set of conditions, homophobia tends to emerge. Warrior-tribe people, especially in harsh environments with few resources and much competition, tend to push for a "breeder" mindset that encourages very particular patterns of family identity (including Patriarchy) which encourage large numbers of children for the next generation of spear-carriers. In places where tribes are not so dense and resources are more plentiful (e.g. rainforests), you tend to see more egalitarian societies and less issue with the idea of sexual identity. Of course, the three major religions on earth (Christianity, Islam, and Hinduism) all evolved out of warrior societies, and tend to promote a strong line of definition for gender roles as inherent in the "in-group" definition.

It's important to realize this for what it is, and not confuse it with an instinctive disgust for homosexuality or other "deviance". We are taught to think of those things the way we do, whether we realize how much influence those teachings have on our instincts toward xenophobia. There are many factors which limit our capacity for empathy, and I think a mark of civilized (or "evolved", if you prefer) intelligence in humanity is the capacity to recognize those limits and the source of those xenophobic ideas, and to choose to overlook them and "learn better". 

To put it another way, while xenophobia is a natural instinct that evolved, the fact that people here in SE Missouri tend to hate black people is not based on a natural revulsion to dark skin, but to social training that they absorb from a very young age, here in Klan country.