@Sakai you're the one who fails to see what's wrong here, what we are saying here is his action is not excusable by him being in puberty, or him feeling guilty since he is Actively and Consciously creeping on her. Feeling guilt just shows his aware what his doing is wrong but that alone doesn't excuse being a creep, specially when he doesn't stop.
In another note if that's your take away of "feeling guilty" then anyone who committed "crime of passion" and ended up killing someone is excused since they didn't actually want to do it, because they couldn't just stop them selves from doing it.