Any answer to the original question that goes much beyond "because that's the aesthetic" is really doing it wrong.
I mean, one could talk about WHY that's the aesthetic of cyberpunk. Why everything is sexy, super-focused on style and appearance, and what that says about how cyberpunk views a future that's been shaped by relentless capitalism and the comercialization of all aspects of human life.
But any answer that doesn't start with "Because that's a basic aspect of the whole Cyberpunk aesthetic, and the more an artist moves away from sexy-everything, the more they are in danger of drifting out of the Cyberpunk genre entirely" is building on a foundation of vaporware.
After all, a cyberpunk gutted of sex is just Warhammer 40,000 without space magic.