What the actual hell? This series of events makes literally no sense. The adults obviously saw something was up and questioned the kids, otherwise they wouldn't have bothered getting involved. The boys ran away because they're obviously doing something they shouldn't, and they find the girl is crying her eyes out and even pissed herself in fear long before they even showed up to "help", and they assume she's somehow doing something wrong because they find the panties of the girl who was literally just being abused?
This would not happen anywhere. Not even Japan with its frequently judgmental attitude. Starting to feel like the author doesn't really get out much or has some sort of fear of humans.
I mean lets be real this whole series is messed up on some level, but this is some really bad writing. Might as well had a martian show up and stick a carrot in her butt too for good measure. At least then the adults would have a reason to be like "wut"