I'm not trying to excuse the media by any means, but given the extent to which people--especially privileged people--can self-select their peer group IRL, it's not always a given that they will see diversity outside of the media either. When I visit my parents in update PA, I generally do not see one single person who is not of European descent the entire time I'm there. Even in diverse areas, people tend to clump up with other people like them. On paper I live in a very diverse area, but if I had enough money to live in a bougie gated community, I could absolutely avoid seeing anyone who wasn't rich and (probably) white unless they were a service worker of some kind. Media is definitely a problem, and like I said I don't want to give the impression that I'm letting it off the hook, but it's good to keep in mind that in some areas, it's far more diverse than what people see in their every day life.

ETA: I should clarify that I meant it can be more diverse in terms of race/gender/sexuality than what some people are seeing. In terms of your original post about how it totally over-represents thin, attractive, young bodies, I think that totally holds no matter where people are.