Shhhh. Herding European pussycats is much easier for Powell and the administration if they think Powell is 'one of them.'
Do you really think Powell made this decision. This is not president Powell's administration. This is the Bush administration. When the question came up, Powell asked Bush what to do, and Bush told him. Powell came out before the press and said what Dubya told him to say.
That is way the game is played in Washington D.C. Everyone who has been in D.C. more than 20 minutes knows that Bush calls the shots. Anyone who tries to call his own shots in the Bush administration will find his a$$ has been kicked so hard it will likely come down somewhere west of Winston-Salem. They never get a chance to do it twice.