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.
As far as I can tell, the original meaning of based came from the alt-right, meaning something is praiseworthy because of how unwoke it is. So yes, being chauvinistic would be considered "based" by the original users of the term.
But thankfully the term has more recently been claimed by less misogynistic/racist/homo-/transphobic groups, to mean praiseworthy because of something's opposition to hate. Unfortunately, both usages now coexist and it can be hard to see which one someone means, without adequate context.
It came from a rapper. One of the Lil's, possibly. He was reclaiming an AAVE variant of "debased", to mean something positive about himself. It's all recorded in the ancient texts.
One might note that rappers aren't particularly noted for having sensible and kind cultural takes
"Based means being yourself. Not being scared of what people think about you. Not being afraid to do what you wanna do. Being positive. When I was younger, based was a negative term that meant like dopehead, or basehead. People used to make fun of me. They was like, 'You’re based.' They’d use it as a negative. And what I did was turn that negative into a positive. I started embracing it like, 'Yeah, I’m based.' I made it mine. I embedded it in my head. Based is positive."
not to say I disagree, but this reclaiming is pretty based.