But Sazed hasn't avoided intervening - in fact he quite clearly does through Wax and the Kandra, its simply that he only intervenes in certain ways, paraphrasing him "To maximise the possible good outcomes for everyone". Part of his power set is quite literally to take control over certain people, and even if he only uses it to do good (by his measure of good), he is still removeing their autonomy to meet his own goal of harmony.