While I understand why it can benefit the setting/worldbuilding, I kinda hate the pro eugenics mindset common in shounen, and generally in fantasy

If you aren't new to fiction, you have probably already ran into a story where almost everything about a character's power and importance in the story is based on their bloodline, heritage and/or genetics.

Obviously it can be used to explain why the characters we focus on are so extraordinary, why they got their powers. However, I think that on a meta-commentary level it's a bad look on our society, in terms of message and world view.

For example:

In Naruto, if your family name is not Uchiha or Senju(Uzumaki), you ain't worth shit. To a lesser degree, if you weren't born to a big name clan/person with a hereditary jutsu you might as well change your name to "fodder" in most cases.

In Dragon ball, if you weren't born a saiyan, good luck ever catching up with the recent power creep buddy.

In JJK, 80% of a sorcerer's power is gained at birth. Got a shit CT or shit CE reserve, or god forbid, both? Good news! You are eligible for an official fodder certificate.

MHA.

What kind of defeatism riddled brain thinks everything about a person is the genes or last name they were born with? We are made who we are by life, not at birth.

Is this mindset common among japanese? It just seems so common in manga for some reason.