I disagree that our morality is secular or good. Our morality is predominantly altruism, and that comes from the Bible. It’s there in the Old Testament, but it is more pronounced in the New Testament. Altruism is the idea that a person must live for others, not for himself. It also makes it legitimate to expect others to live for you. This is an evil ideology, because it turns a person into a sacrificial animal. The Bible makes altruism ultimate, by expecting a person to live for God (in reality, for priests and for majority view), not for himself. In this light, the Original Sin doctrine makes perfect sense: make a person feel guilty, so that for the rest of his life he must serve god in an attempt to absolve himself.
In our culture the ultimate praise is reserved for failure, misery and death (e.g. Mother Teresa), and ultimate disdain to those who are not shy to be selfish (e.g Newton, Steve Jobs). For more info on why altruism is evil, read “The Fountainhead” by Ayn Rand.