Americans greeted news of Osama bin Laden's death with a celebration of the payback it represents for the deaths of nearly 3,000 Americans on September 11, 2001.
As former Vice President Dick Cheney said on hearing the news, “Today, the message our forces have sent is clear—if you attack the United States, we will find you and bring you to justice.”
This is part of the American psyche. A great power cannot allow itself to be attacked and harmed without rendering retribution. Every day bin Laden drew breath after 9/11 was a rebuke to America.