Tao doesn't preach. At most it describes the results of various behaviors, based on the four basic principles of nature. However, it goes on to warn against those who preach, or try to tell you how to live. It warns against contrived, or consciously manipulated morality.
Because nature is dynamic, and contrived morals are stiff, contrived morals go against nature. Furthermore, the purpose for these morals are usually not better living, but greater control, either for yourself or for others. By dictating your morals, other people feel a sense of control over your life, and its no different just because you dictate your own morals. The bottom line is that whether you're living better or not has no bearing on morality, only if your more controlled. Nature is not something that can be controlled; it controls itself. You needn't impose your control on it, or let others impose their control on you.