I think this is all made a bit complicated. I think it's obvious that even without a belief in a higher power, it's just the decent thing to do to try to help people and cause as little harm as possible. Many religious people go to church, perform their rituals, absolve their sins, then as soon as they leave church, being squeaky clean, they do wrong to people and absolve it next week.
Some of my relatives who live in deep in the buckle of the Bible Belt call it: Saturday Night/Sunday Morning morality -- referring to how some guys can go to a bar or even a strip joint...get drunk, get in fights, and then act totally transformed on Sunday morning. It's partly hypocrisy, but also an illustration of how our behaviour and "morality" is influenced by others around us and the setting we find ourselves in.
Whether the church part is a benefit or a possible harm depends on what kind of church it is, and what sort of message is received. If they are spending the working week cutting and thrusting in a ruthlessly competitive business, and being bombarded endlessly with ads that they need to buy more stuff, that Sunday morning in church might be a reminder of how unchristian their modern, everyday life is. But if it's one of these newfangled prosperity-gospel churches that worship the accumulation of wealth and glorify greed as a virtue....forget it....they'll end up worse than ever!
The Golden Rule is common sense. I don't like it when people do wrong to me. Therefore, I should strive not to do it to others, since they are human just as I am. If you need a list of commandments to act decent, you have sociopathic tendencies, imo.
If I ever get around to writing up a signature line here, it will have something to do with my observation that most people, representing all forms of religious beliefs and no belief, form their arguments based on the principle that 'everyone thinks like me'....or 'should think like me'...I'm not decided yet..... And apply that principle in deciding whether or not people need religious or supernatural beliefs, and what sort of beliefs everyone should follow.
But the problem here is that the Golden Rule may be common sense to you and to me, but that doesn't mean it is common sense to all people, as you have alluded to by noting that someone who is a sociopath does not have the capacity for altruism to know implicitly how to act. There is no sharp dividing line between "normal" and being a psychopath or sociopath. There are a lot of people in the grey zones who will have to follow some sort of deontological, rule-based morality if they are going be law-abiding, productive members of society. If you've ever met any of the "Bikers for Jesus" types, who claim (and likely make most of it up) to have been dangerous outlaw bikers before they were "saved," and would be drug-dealers and killers if not for Jesus....just take them at their word!
