Honestly, I think a lot of this comes down to money and power. I look at Bishounen aesthetics and it seems absolutely self-evident to me that when women have a choice, a lot of them will go for young and thin and tall and winsome and well groomed with nice, flowing hair. And the mere possibility of this dismayed a lot of competitive-minded men, because suddenly the body type that impresses other guys has little to do with the body type that "all" women supposedly fantasize about. How offensive and unthinkable to consider a world where football players and marines might lose out to less alpha looking dudes. That's what I hear behind a lot of the conservative panic about effeminacy in manga. Because after decades of the media presenting one thing they assured us all women found attractive, women could get something radically different from somewhere else, and suddenly these houses of cards about women being "less visual" and "less sexual" and the rest toppled.