I noticed increased frequency of posts in places like r/rpghorrorstories, that describe a situation where the player brings a tiny veiled or just a shameless copy of a popular fictional character - Sokka, Scanlan, John Snow, Walter White - except "more based" or "less of a cuck". What follows is a story of the player doing some horrible manosphere shit.
I know that a lot of posts on places like these are fake, but in this case I kinda hope they are. Or that it's all the same guys at different tables. Either is more comforting that an idea of an army of incels trying to rp their extremely toxic fanfiction on the table.
"Based" was around a long time before the alt-right started using it. IIRC it originated in hip-hop.