That's a valid point, especially in a case like this one where they aren't adults yet, plus they're struggling with the reality of a minority relationship.
I do see similar situations in many manga where the main characters are intelligent, capable adults and the crime or attempted crime is not necessarily something that would be considered shameful for the victim, but all they do is ensure the perp never bothers them again. That is still worrying for me.
Also, even in ones like this, regardless of whether the actions of the MCs are understandable or not, I'm still disturbed by the thought that there's a guy wandering around who thinks it's ok to force himself on someone (let alone a minor).
...And that is when I have to remind myself that it's fiction!
I am sorry but why you think that in a pedo case, police is notified for the crime? Japan or not, just like rapes, only a small portion of pedo-rapes are reported and an even smaller amount goes to court....then some perprators will be found guilty (enough evidence, not stuck in technicalities, etc) and face 2 to 3 years of prison. If the pedo shows a good conduct and say that he/she is sorry then the sentence is reduced to 6 months...and all that is the good scenario....
Yes, I think what bothers me more than whether someone in an individual manga is left to roam free, it's the fact that soo many mangaka themselves don't seem to burger about it most of the time. It's as if they feel their story is satisfactorily resolved when is no longer a problem for their MCs. If they want us to buy into their while fictional world, I feel like they can't expect it to feel like a properly resolved ending when the perp is completely ignored. The manga ka could write SOMETHING, right? Even if they're not brought to justice or don't see the error off their essays and fix their behaviour, they don't even have anyone show concern.
(Well, like I said, I have remind myself it's fiction, so nobody's really in danger.)
"Oh good," they all think, "Guy who attempted to rape someone didn't succeed, we're fine...so let's just let the would-be rapist go on his merry way to assault other people who have nothing to do with us or this story. Not our problem."
(No, I do get that it would complicate the story and, basically, the creators just want an antagonist to cause friction and move the story forward, but it's soooo common in manga that people who attempt to rape, kidnap, injure, stalk, assault, blackmail etc. are ignored once it's no longer the main characters' problem...and it bothers me every single time.)