Steering Wheel Vibrate problems of the 2012 Mazda MAZDA5

I had noticed my steering wheel shaking slightly when slowing from highway speeds when my Mazda5 had 13000 miles. I serviced my car at 18000 miles for an out of state trip, at this time my brakes were at . 08mm and in good condition. During and after my trip the steering vibration became so extreme when braking at highway speeds that I avoided further driving on the freeway for safety. I returned the car to the dealer service center and they checked my rotors. They informed me that "run out limit" on rotors is . 04mm and mine were at . 06mm and were so warped that they could not be resurfaced. This part is not under warranty and the service center was unable to make a determination if this was "wear and tear" or a "parts defect". I asked for an explanation as to how my brakes have never been changed and are still in good condition; how it could possibly be "wear and tear"? they directed me to Mazda customer service to get approval for the service. After a few days Mazda agreed to repair my Mazda5 under "goodwill, one time only" and not under any sort of warranty. I feel this is a breaking system defect and should be investigated.