>>718717665
I would like to know as well.
It has to be a culmination of multiple things, but my guess would be that it began by girls who got mindbroken by beauty standards (they remind me a bit of bratz dolls) and when they had an outlet to create their "idea" of beauty, they made some kind of proto version of what you posted. When I went to school bulimia was not that uncommon and the issue with it is that the people have a warped sense when they look at themselves, probably kind of similar to what people experience who take the bog pill.
Thanks to the internet, people who might have been niche outsiders, were able to find like minded people and I would imagine they reinforced each others view, which eventually lead to modbeasts.
So a combination of warped beauty image and group reinforcement would be my guess.