I have never understood why fashion seems to be geared toward inflicting pain. To wit: stiletto heels, corsetry, foot binding, head binding, neck rings, starched collars, horrible chemical gloop (makeup), models with eating disorders, etc.
What, I can't be beautiful unless I'm in agony? Why don't I down a few arsenic pills while I'm at it?
In same cases it's the trophy effect. It sends the message of "I'm high class and don't
need to work, so I can decorate myself with impractical crap." Crippling things like foot-binding could make someone largely unable to fend for themselves, and it would become a status symbol for the man who could afford to "own" a woman he had to take care of. As is often the case, it starts out as nobility showing off how much better they are at life, and because throughout time people always want to be the popular kid, everyone else starts emulating the behavior to look "high class."
We don't do the physically crippling stuff quite so much these days, but it's a similar idea. "Natural beauty" is
common, it's what everyone starts out at. People insist on being better than common, so they work on appearances that don't naturally occur, and often enough, going outside the body's natural range can predictably lead to pain. If some factor is considered attractive, people assume that taking it to the extreme is even more attractive. If being overweight is a mark of status/health? There are still places in the Middle East and Africa where force-feeding small girls for marriage is common. If being thin is the standard of beauty? The familiar western result of anorexic models and not-quite-human-shape Barbie dolls. Being thin
and having child-bearing hips? Organ-crushing corsets. People make the radical assumptions, goals that are not naturally occurring often require products to achieve and so are encouraged by companies who sell them, and everyone else buys into the social norm and wants to copy the "beautiful nobility", and the cycle goes on.