What do emotions have to do with a moral code?"

Because a pang of conscience IS an emotion, through and through. Guilt, shame, anxiety, etc. If an animal can feel these emotions, it follows that they can experience conscience, as evidenced by a dog's reaction when it does something it knows upsets us.

"Do you think the majority of people are thinking before every action, 'will this benefit society?'. I don't think so."

When a man has a one-night stand with someone he hardly knows, do you think he's thinking "Ahh, this will help spread my genetic material into a wider gene-base, hence increasing the chances of my offspring to compete in the world!"? Come on, Sam.