While it is true that a bike is more stable with a lower center of gravity, that has nothing to do with this discussion. This discussion is about how you generate traction to "hold" the corner. For the purpose of this discussion, the resulting force vector is a straight line through the center of gravity and tire contact patches (or, rather, a point on the curve between the tires) and the net torque is zero. There is no net torque when you are properly balanced and if you are fighting a torque, then you are doing something wrong (and probably in the process of falling).Yes, center of gravity has much to do with cutting corners.
When you are turning, the torque caused by two opposing forces (the horizontal component of the weight acting on the center of gravity and the horizontal component of the reacting force to the tires this being not vertical but on the axis joining tip of the tires to CoG as in the case of grip) must be minimized not for the sake of turning itself (always 0 since the bike is in balance) but for the sake of stability.
And the way to do this is by lowering the CoG.