I think you are being way too extreme in your analysis op and it means it doesn't ring true.
Like the bathing suit. You happen to live in a place where men wear trunks, go to France and you will see a lot more male crotch hair. And some men will remove it.
And there is actually quite a wide variety of female bathing suit styles that are fashionable.Lots of options with shorts.
Now the super-sexed up bathing suits in things like Sports Illustrated are not like that, but why would anyone expect them to be? The whole point of them is to be highly sexualized, so by definition they aren't modest, thy push all the boundaries. If you go to a beach those kinds of suits aren't typically the majority and no one thinks, gee, why isn't that middle aged plump woman wearing a skimpy bikini? I don't think anyone expects most women to look like pin-up models. Just like we don't expect most men to look like Chris Pine. Lots of women and men might like to look like that, but we all know that's not realistic.
A few people have mentioned that girls in particular go through a phase of trying a lot of the more sexualised fashions on, and feel pressure to do so. That's true, and it would not be a bad thing if that pressure were lesser, but to some extent I think it's natural that young women are trying to get a handle on their sexuality, which is new to them. They don't understand all the social implications yet, they don't really know who they are, and their hormones are also ramped right up. And the element of female social hierarchies is huge there, teen boys are not the ones driving the bus on these things, overall.
It's also the case that teens in general have a hugely elevated sense of being watched and judged compared to adults, this is a well recognized psychological aspect of teen development, and it means they feel a lot more pressure, in many cases, than is really there.
Teen boys social hierarchies exist too, but they are structured around different things, and they are a lot simpler.
Schools and parents typically try and help teen girls through all this by not allowing them to go all out in certain settings like school, and by playing down the importance of trends, and just being adult and reasonable. Tbh I am not sure that feminism has always been helpful in this area.