One is passionate because one thinks 'I' is real, the key to the subject/object split. Without 'I' there is no one who experiences passion. So in order to return to oneness with The Absolute Tao (ie; The Secret of Life), one 'strips oneself of passion'; that is to say, abandons the subject/object split.
I agree that one can be passionate regarding the "I" concept, and this can lead to the same trouble that any other like-dislike passion can lead to.'Everchanging' is what you perceive as real; how it only seems to be, just as the monks perceived wind/flag movement as real, but which turned out to be moving mind. But even moving mind is an illusion. As one other monk put it:
I agree that my perceptions are subconsciously processed, and are only a representation of reality, not reality itself. The map is not the territory."From brilliancy I came;
to brilliancy I return.
What, then, is all of this?"