Every community/instance is able to draw the line for what is or isn’t NSFW where they want. That being said, in my eyes, there is nothing NSFW here. From modding the anime community, I have found there is a non-trivial segment of the lemmy population that tends to dislike any kind of anime/manga content when they see it. That can come in the form of a user downvoting every post in a community on a given day or frivolous reports because there is some piece of media that features a character <18 years old, even if there isn’t anything lewd at all.