They are teenagers and drawn as bishounen, and those are what sell in japan and most of those LN have "ordinary highschool students" as PoV MCs. What did you expect as protags that your
japanese reader would identify with? Musclemen like Frazetta's
Conan the Barbarian or guys like Travis Touchdown?
EDIT: Japanese readers would much rather identify themselves with characters looking like
Hidenori and
Tadakuni.