First thing, I have to agree... if there is NO traction, 4WD is going to result in 4 Wheels slipping.. not gripping, remember there is NO traction
That is not entirely true and does not apply to 4WD's the same way it does to FWD's
Front Wheel Drives handle better because they are pulling the rear through the corners and not pushing the front through them. So the back of the vehicle is less prone to slide out and around you.
4WD's are still pushing from the rear... even with the front pulling. When in a corner that "push" occurring in the rear, is more likely to cause the rear to swing out... and around. If that happens and you are in 4WD then the front can help to correct it, assuming TWO things.
1: There is enough traction for the front to counter the rear.
AND
2: The driver has enough skill to control the vehicle and properly guide it out of the slide