The short question is: if we stick to The Way in Tao Te Ching, won't that be sinful?
That's because, The Way seems to be the "most natural way". For example, if we know the manager likes flattering, we flatter her and then once we know she is friend with us, we backstab our coworkers in front of her. If a man is with a woman and she is totally drunk, the natural way could be "to make a million babies with her" (as in the movie American Beauty).
Details: even the verse 38 of Tao Te Ching, states that "Top virtue is not (appearing to be a) virtue... if we lose The Way, then we go by Virtue, and if we lose Virtue, we go by Human Compassion (仁) or Humanity, if we lose Human Compassion, then we go by What Is Right and Responsibility, ... so The Way is the highest.
However, The Way or The Most Natural Way can be very cruel. It can be the most selfish, without conscience, almost like a sociopath or psychopath. Do it the most natural way, it can be seen as deserving to go to hell in Buddhism, Muslim, Christianity, Catholic, and many religions. For example, if a person can earn $100 million but he has the ability to take $99 million and leave scrap to people who work just as hard as him, he would take $99 million, because it is "the most natural way".
Here, I will put down Thomas Cleary's translation and the original text of verse 38:
38. Higher Virtue Is Not Ingratiating
Higher virtue is not ingratiating; that is why it has virtue. Lower virtue does not forget about reward; that is why it is virtueless. Higher virtue is uncontrived, and there is no way to contrive it. Lower virtue is created, and there is a way to do it. Higher humanity is created, but there is no way to contrive it. Higher duty is done, and there is a way to do it. Higher courtesy is done, but no one responds to it; so there is forceful repetition. Therefore virtue comes after loss of the Way; humanity comes after loss of virtue, duty comes after loss of humanity, courtesy comes after loss of duty. Manners mean loyalty and trust are thin, and disarray's beginning. Foresight is a flower of the Way, and the beginning of ignorance too. Therefore great people dwell in the thick, not the thin. They abide in the substance, not the flower. So they leave the latter and take the former.