Pretty much. Unless one wishes to argue that the Patriarch of the Jades is himself a fool who would rather see the land poisoned by Dhar than allow his rivals to have any political power we can only conclude the rituals in their present form are of no to little use (less than the effort it takes to perform them).
Life is nowhere near this simple. Someone can be smart and wrong. Someone can be well-intentioned and wrong. Someone can be extremely skilled in some fields and still be wrong about others.