I am not saying this is what happened...but all indications are that it is similar to what happened.....
if an officer pulls you over...and you innocently reach under your seat for your wallet that fell earlier while you were driving, and the officer orders you to NOT reach under your seat (for obvious reasons)...and the officer then asks you to exit the car so he/she can feel safe that you can not reach "whatever may be under the seat"...and you refuse.....and the officer continually orders you to exit the car...and you still refuse......exactly what is the officer to do? Stand there wondering when you may reach under the seat for a gun? Turn his back and walk back to his patrol car giving you the time to reach under your seat for the gun? Leave you alone and ask you to drive off and have a nice day?
It is easy to say they were too aggressive....but exactly what should the officer have done when he refused to leave the car AFTER reaching back for something several times?