I had a friend who irritated this part of the internet with fanfiction and got death threats because of it! It's really stupid lol they're called "antis" because they're anti everything.

They're so insane that they have called characters who knew other characters (all fictional characters, treated as seriously as though this was real life, mind you) when they were underage but ended up dating when both characters were canonically both above 18, they call the older character in that scenario a groomer. With their full chest. When no grooming activity has taken place. It's very black and white. Also very "you should have known you would have offended me with that idea"-y which is very not good for creative work areas.

This is the side of the internet that infantilizes full grown adults, thus making a 20 to 23 year old age gap "problematic" (in heavy sarcasm quotes because I pretty vehemently believe there is nothing wrong with 2 consenting adults being in a relationship together. Problematic is a useful word still, but this just is not what problematic looks like)