The 'swirl' affect on a fan on a jet engine is 'reacted' by fan exit guide vanes in both the fan and the core. So while there is a torque in one direction from the fan, the exit guide vanes provide a counter torque in the opposite direction that is nearly equal to the fan torque. The final stages of the turbine work similarly. Hence the net torque from the engine that ends up being applied to the airframe is minimal (plus minimizing the exit swirl helps efficiency).
Some propeller engines do more or less the same thing by using counter rotating props.