as a retagging of the series to better warn people
That's awesome precedent you just set. I guess we're onto retagging on single chapter /arc basis.
I insist then that every battle shounen (they were beating each other pretty hard in Bleach, and Naruto had some really gruesome scenes if I'm remembering things correctly), as well as "historical" titles (Golden Kamuy, I'm looking at you) should be tagged with "gore".
Also, every yuri with unwarranted female attention and forced kissing, as well as bl titles that take use of "I'll rape my way into your heart" trope should obligatory be tagged with "sexual violence". Shoujos with kabedons also tend to give off assault'y vibes.
What I'm really trying to say though, it's rather dumb idea, and you just happened to react to something that was put in front of your eyes. I don't get what's with recently woken victorian sentiments in the "community", but it's starting to be pretty annoying.
"Problematic", heh. "There's a paper in that!"