Fish do not go with the flow. If they did, there would be no freshwater fish.
In fact, there are entire genera of fish that must swim *against* the current in order to breathe.
Reaction is the swimming against the current to breathe. You must swim or be either drowned or swept away. Adversity shapes understanding. Right speech and right action are dictated by circumstance and the path that will result in the greatest compassion. Kannon himself, the purest embodiment of perfect compassion, will rage and terrify if it is what is necessary to save a life. And sometimes to save a life you must take a life.
One of the primary tenets of Zen Buddhism is do not kill, yet Shinto believes that death is necessary. Yes they are contradictory, but in a complimentary way. Death makes way for life, and to not take life generates an appreciation for life.
Shugendo in many ways appears to dwell in paradox, but paradox can only exist in a world where separation exists.