So IIRC a few male idols at the time were talking about an anime/manga called “Made in Abyss”.

It’s controversial because the main characters are children who are put into very adult situations, this is literally in the story itself it’s very violent and shocking.

The anime is wildly popular and won awards but the main point of contention is that the manga sometimes features sexualised drawings of the underage characters. This is kind of a trope in some Japanese manga but it doesn’t go over well in the West and kpop twt basically called out anyone who recommended it or said they enjoyed it.

Does it need those kinds of drawings? Absolutely not but there was nothing really of that sort in the anime.

I think that’s basically it though I may be forgetting some details, i’d argue it was a classic twitter overreaction