It would seem that the idea is to avoid taking it upon oneself to enforce ethical standards - the higher ethics, i.e., adhisīla. See the related question, What is meant by “higher ethics,” etc., in AN 3.84 (Vajjiputtasutta)?. It might be worth noting that the ability to “encourage someone in the higher ethics” is praised in AN10.36. So there seem to be some subtle distinctions that are not explicit in AN5.106.
David