"For if ye love them which love you, what reward have ye? do not even the publicans the same?" - MT 5:46To follow my previous commentary on free will, we see here a challenge posed: if you only love those who love you, what makes you better or even human? Even the lowest of the humans show their own affection, the same with animals.
So we see the common human behavior, to care only for those who care for you, as the default human action, the default animal action. The selfish choice, the modern argues, is exercising free choice. In reality, this "free choice" is the non-free choice. It only demonstrates that one has done exactly what would be expected from any number of animals.
To go above and beyond that though, to make a choice beyond what even the publicans do is breaking through beyond the basest mental state, where no thought is required, to a higher mental plane. To truly exercise free choice, to fully realize the individual by going beyond the individual, as in "he that loseth his life for my sake shall find it."