There's an American novel called, "A Brother's Price" and it's basically this kind of story except set in an alternate US.Furthermore men grow being taught by their own families that women are dangerous and shouldn't be trusted. While Sou's little sister didn't want him to end up detached again, the older sister and his mother said they were willing to be hated for his protection. If anyone is hammered that in his head since childhood and then had to periodically donate his semen it'd make sense he'd start becoming bitter eventually.
We forget since all the women in this guard academy are harmless and faint for a few seconds of contact, but the fact that there IS a Guard Academy to begin with has heavy connotations
It goes pretty deep into the world building; a man having his knees exposed is considered shameful/lewd, unrelated women will band into one family to share a single husband, men getting kidnapped and drugged for "cribs", STD's are an issue, and even goes into how a man can abuse power against his own family by virtue of being a literal precious commodity.