torque is angular force. It requires force to move the servo control horn. The more torque the servo has, the more force it can move that surface with. Larger surfaces require more force to move. If nothing were fighting back against the servo, then there would be no force required to hold the surface deflected--no torque. However, we know that as long as a surface is deflected into an airstream, there is force fighting back. The only force available to hold the surface deflected is that from the servo--the angular force created by the motor inside the servo--torque.
Therefore, torque is torque--whether it's the force required to move the surface, or the force required to balance the opposing forces when the surface is deflected.