Think of them like the Japanese equivalent of the old "movie of the week". The degenerate guys may see this as masturbatory material, but hopefully scares the hell out of teen girls and keeps them from doing obviously stupid things "out of curiosity".
I personally can't read series like Ura Account Jyoshi, because it's pushes the "destroy the MC" narrative and is barely a step above hentai, but it definitely is set up with a "doing this will only end badly" moral to each storyline.
It just seems like the Japanese are far more extreme with their life lessons. Instead of lifetime movies, they get a rape manga