I run into an article where I find one sentence really confusing. It is an excerpt from the paragraph below.
The reduction of young women to an increasingly narrow range of conformist standards around “beauty” is part of this backlash. It makes girls deeply unhappy and obsessively self-policing. Teenage girls compare and contrast like no one else. They see every imperfection and measure it against someone who is paid to look perfect. They feel lacking, worthless and angry. So they punish themselves. The all-purpose rubric of self-esteem comes into play, but to have self-esteem in a culture that only values certain “looks” requires rebellion.
I'm not sure what "rubric" means here. Some kind of instruction or guide? And the use of “all-purpose” seems really bizarre. I'm also not quite sure what "requires rebellion" means here. Rebellion against what? I'm guessing... rebel against the culture that only values certain looks?
Could someone help me understand this sentence?