Umm... Rui Tsukiyo is a man.
That being pointed out, the entire rest of your post is basically wrong.
Especially:
It literally is.
Even Nick admits it.
I have noticed there's been this weird thing, over the past few years, where any time there is a controversial anime/manga, people try to end the controversy immediately by saying "oh, it was written by a woman."
Same thing happened with Goblin Slayer. Which was also written by a man.
It's getting kinda stupid, TBH. If you wanna defend something, then defend it on the merits of the work. But don't claim something is okay because a woman wrote it. Especially if that's not the case.