I don't know how accurate that number is.. but the idea is that he's responsible for those deaths, just as Hitler is responsible for the deaths of millions of jews before and during WW2. There's nothing Obnoxious at all about celebrating justice coming to a man who intentionally murdered Civilians because he didn't have the balls to fight his "enemys" Military. He's been behind attacks on several Embassys as well as being connected to the previous World Trade Center Bombing in 1993.
He was a VERY evil dude who didn't give a shit about anyone who didn't follow him. His forces in Afghanistan raid their own people's villages and kill innocents, then threaten the rest of the village that they'll do the same to them if they don't aid them in hiding weapons and reporting on Foreign Troops.
Now Iraq is a VERY different thing altogether.. but as far as Osama Bin Laden and the war in Afghanistan is concerned, he needed to be stopped and the war was very necessary.