Because people who want a shonen animes vibe in their work replicate terrible anime tropes to achieve that. It's for the same reason the stupid back of head scratching and pushing flashing glasses up nose with middle finger tropes get used.
If they don't like it they won't include it. If they do include it then they are looking to achieve a more authentic shonen anime vibe, adding in an SJW style critique or lecture in the middle of that would spoil the authenticity from their pov. There is no reason they just have to write a critique of the culture they are writing about, being from a different culture is not a reason.
Also, I find it amusing that you feel the need to insult white people for failing to attack another cultures way of life.