People care what you look like. Clothes, tattoos, piercings, all imply things about the person you are looking at.
In this place, fashion extends to the body, as well. Genetics can be worn or discarded like clothing, so why aren't they? Entire factions are founded around modifying one's body. It can easily be said that they are a fashion-faction, even if it is integral to the mindset.
Hemotopians use, abuse, and modify fashion to their whims. A particularly bad fashion faux pas is grounds for ostracization. Remind you of anything?