From the same website:
There is nothing that you did in the US Navy that is more important than what you are doing now in directing the 45,000 dedicated men and women of the Transportation Security Administration. By your calling yourself "Admiral" you are telling we screeners, as we now risk our lives everyday for our fellow Americans, that this is your "retirement" job.
It is like we are your "step-children."
You are now responsible for the safety of the tens of thousands of people who fly the American skies each day and you are also responsible for the 45,000 screeners who search and find and you are also responsible for the 300,000,000 Americans who trust you to keep our economy rolling.
If they believe that, believing that Stone is no longer entitled to call himself "Admiral" is nothing!