I'm about as good a counter example to the myth that eating disorders are caused by "unrealistic body standards' set by the media/Disney/Barbie" as you will find.
I'm male. I developed AN when I was 14, in 1977. I discovered by quite by accident that when I withheld food from myself, I would get a temporary relief from the negative feelings I had about myself. It had absolutely nothing to do with body image. I had no desire to become thinner, and I was only vaguely aware of how thin I had become. I call it a "temporary relief" because my behaviors were making things much worse. My body and my mental health were failing. I was increasingly resorting to restriction to deal with that, which put me into a very dangerous cycle. When I finally reached out for help, I had no idea that there was such a thing as an eating disorder. I was helped not by an eating disorder specialist (if there were even such things back in 1977) but by an addiction specialist. All the other kids he saw had drug problems. There's not so much of a difference between taking drugs and restricting to deal with hard feelings about yourself.
Fast forward about 30 years. My 9 year old daughter suffered from anxiety. She too discovered that withholding food from herself made things temporarily a bit more bearable. We didn't notice at first, because she was always a picky eater, but the data showed that she had stopped growing. She has been in therapy and specialized eating disorder treatment for 6 years now. She has been a normal height and weight for about 6 months now.
It's probably true that media images and pressure to be thin cause some (particularly adolescent girls and young women) to be unhappy with themselves, and may lead some to try behaviors like restriction and purging. But nobody is going to stick with them unless they get a "reward" of some kind from the behavior, whether that's some temporary feelings of relief, feeling in control, or something else. It's these rewards the trap some like myself and my daughter into the cycle. Our brains are wired to feel these rewards, and we'd probably never know if we didn't fall into it.