He was not a traitor in the same sense that the Vichy French did not support the Nazis.
When he traveled to Afghanistan to join the Taliban, it was well known that the Taliban was providing comfort and support to al Qaeda which had already professed strong anti-American views. Osama bin Laden was a target of the U.S. long before 9/11, and only an idiot would fail to pick up on strong anti-American views when actually in Afghanistan. Further, were he a loyal American, he would have helped the coalition forces in dismantling the Taliban, but he was instead captured gun in hand, which he toted around with Americans in-country.
But wait, since the liberal b@stards in this country want to eliminate the Pledge of Allegiance, I guess no one's a traitor anymore. Let's all feel "sorry" for Osama Lindh because no one's responsible for their own actions.