I think it is a cultural difference. It is not uncommon for the Japanese to avoid confrontation. Its also frowned upon for someone in Japan to be stalked and helped after they've acknowledged the stalker. For example, a man has been following a woman, trying to talk to her, bringing her gifts; The police are more likely to help the woman if she did not respond or interact with him because they believe it to be a form of invitation if she does respond. By acknowledging this person existence, you allow them into your life.
