I always play nice. You just dont like it when I point out the flaws in your arguments. Some of what you wrote is true...some isnt.
Namely your assertion that since our upper body is "free" it must counter to the rotation of the lower body is oversimplified to the point of being wrong.
While it is true, for every action there is an equal and opposite reaction, it is inaccurate, and incorrect to view this issue as upper body vs. lower body, in reality it is upper body (and its 1 rotation of axis) supported by TWO legs, each with their own independent rotation of axis (hence 1 axis, supported by 2). These two axis, operating under the one upper body, provide the upper body stability. You can play with this at home...put a ruler on a pencil and rotate the pencil, the ruler will rotate also, but if you have two pencils supprting the same ruler, the ruler will remain still.
Now, we had a good discussion on this topic in another thread, and JamT pointed out that if the surface is frictionless, then this gets a little more complicated...but skis on snow (particularily with edge) is not frictionless, so while what I wrote above doesnt provide 100% stablity it does greatley reduce (95%?) the "equal and opposite reaction" that we might expect.
This one of the main reasons why we use "Independent Leg Steering" vs, rotation in the spine. The "Independent" legs part is critical.
Whoah. Just did this. Totally true, and a perfectly fitting metaphor.
One bar stool vs two works as well, but I don't have bar stools in my house.