My guess is because President Bush had a relationship with his Secret Service that included an incident like the one captured in this video from Santiago: http://www.youtube.com/watch?v=PX3aaWlUmpc
A man who knows his President will do something like this for him is not a man likely to bring dishonor to his Commander-in-Chief.
This is one my favorite memories of President Bush.
Everything Soetoro touches turns to crap.
Great link - thanks.