I spoke with AA yesterday. Of course no one knew why. The first answer was "due to 9-11" Aaaarrrrgggghhhhh I then pointed out that the ban was in place prior to 9-11 so they would have to try harder. Next resposne was it is a security issue and we will not discuss it. Finally another managere admitted she had no idea and would check into it for me and call me.
By now I am sure I have a really thick file at AA and will be randomly selected on my next flight.