that's because the flight control computer is flying the rudder for you, only because a few pilots felt the need to hard bang the peddles on a few scary emergency instances and snapped the tail off killing all onboard (airbus in particular had several), now the FCC controls it and as airspeed increases the full peddle deflection of rudder (what you as the pilot, still have control of at the peddles) is drastically reduced to prevent more people from dieing because of snapped off tails.


as Mike touched on, wing design has allot to do with how plane XXX responds to rudder inputs, i've got one jet in particular that hard rudder gives a roll in the opposite direction of the rudder input.