The ancestors needed to be the ones scolding him because they were in a position to. He wasn't going to drag his mom and sister into an incursion to blow up a planet with him. Though I suppose Shuri could have scolded him at a later date. But by the we saw them again, they were good.
Ultimately though it was an Avengers book, not A BP book. We frankly got more from him than we probably should have expected.