@Joel I guess is complicated. In Japan, a woman can marry or have consensual s** at 16yo (marriage age was raised to 18yo like two years ago, tho). So adding a high school girl to the rooster is TECHNICALLY fine for a japanese work. It's a matter of cultural differences.
@NamelessGoblin Just like how slavery was as common as breathing back then? Look, the morality of humans have evolved over time. What you think is wrong Today was considered the norm of before. What will you do if in the future the age of consent is again changed to 25 years old? Wouldn't We all be considered pedophiles to the future generation? What is considered the norm today may turn into a crime tomorrow. What I'm trying to say is, it's good to question the old ways but it's not fair to judge them with your modern perspective. The best you can do is, evolve your mind and continue to question the ethics of everything.
@NamelessGoblin There's another reason that's easy to forget: at least some of the audience will be her age, or even younger. Many authors cast a wide net, probably don't much care if the reason someone likes a character is normal or weird.
I am several times older than characters like Sailor Moon or Asuka from Evangelion. However, those stories are old! When they released, all of those characters were older than me! Fictional character age is weird like that.
As for this story, it leans more into the "everyone likes the guy" fantasy than a realistic portrayal of what the world would be like. But it seems to at least try to portray the latter as well. He has everyone from a middle schooler to an office lady after him to cover the fantasy. Might as well give their perspective then.
It also makes sense in a dating market that's is extremely like this story that girls would basically take any half decent guy they could get. Consider how rough dating can be in the real world right now. There are selective pressures, and unreasonable expectations. It's pretty hard, even though the ratio is close to 1:1. In a hypothetical world like this story, the 80% gender would be desperate. The average 20% would take them for granted and treat them poorly, which the story portrays. MC, simply by being a relatively normal person, is the best chance these girls will likely get for many years, unless they want to jump in as someone's 4th wife or w/e. Of course they're going to try for it.