That was a strange scene. It would have clearly been enough if he had just fetched Murasaki away from there. The whole apologising and bowing part seemed useless extra. While this is certainly not the first time I've seen such scenes in anime/manga, and it's somehow a part of the culture, I can't really see what purpose it served, especially in front of some random punks. The lesson to the little girl should have been to stay away from such folk and not to cause extra trouble, but I'm far from sure losing your own pride appropriately taught such a lesson...