The problem with your use of "selfish" is that there is nothing forcing human identity to be understood in such a way that the 'self' is only your individual being. Your identity includes a large part of your culture, and your 'self' can include other people in the abstract. It's not black-and-white, nor is it a contradiction. You can be selfish for your tribe or your family, without expecting rewards to your individual being for doing so.