Has nothing to do with that.

Genesis geometry doesn't change the rider body position. It changes where the rider is perched over the rear tire. The top tube is longer because the seat tube is moved further back toward the rear wheel. The stem is shorter to compensate for the longer top tube so your arms don't have to reach any further.

I agree that the Genesis geometry makes for a better climbing and descending bike. When you climb, you have more traction, when you descend you are farther back over the rear tire so it feels more controlled.

It's kinda like putting a true layed back seatpost and shorter stem on it except on the Genesis geometry, the crankset is moved back a little to compensate for everything else so it doesn't feel like you're pedaling a Townie.