Good point - keep this as a criminal matter. After all, they'll be extradited to the US after trial and then you can kill 'em anyway.
As for people celebrating this, I think you have to understand the level of hatred some of these populations feel towards the States. It isn't just a matter of "The US supported Israel, so they are the enemy by association". Countries like Korea, Thailand and nearly Malaysia (which, by the way, is one of the most stable and humane places in the Middle East) were hit hard a few years back because the US had bought up vast amounts of the local currency and then dumped it back on the market - the idea being to devalue the currency and thus make it easier to buy businesses in those regions. It worked - the States got good deals on those businesses. It also put over a million people in the area out of work, who were already on the poverty line (and if you're below the poverty line in those regions, you stand a good chance of starving to death). Several governments resigned because they couldn't cope with the devaluation of the economy.
I'm not saying that any of this justifies what happened two days ago, but at least it shows why there is such palpable anger at the States, and why some of these people might celebrate.
Someone said this was a good thing because it made America realize it can't distance itself from world events. Find those responsible and deal with them, then learn from this to develop a less aggressive foreign policy. It took Saddam Hussein to be the one to say that America is reaping what it sowed from the Middle East. While he said that for his own ends, it is true to say that US foreign policy is heavy-handed and can engender resentment among these peoples.
Here in Britain, our own attempt to use our muscle against Ireland sparked terrorist action. Our situation was made more difficult because many of the people in Ireland wanted British rule. Strongarm tactics don't work - I heard the US ambassador say last night that economic sanctions were among the non-military options that could be considered. But it has already been shown in Iraq that sanctions only hit the common people, not the government. Smart leaders like Hussein can then use the suffering of the commoners to foster hatred against those who impose the sanctions.
All points worth considering, but again I want to say I don't feel they justify this horror (I don't think anything can).
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"Spatial anomalies, energy beings, telepathic echoes. You know, sometimes I really miss the Dominion War. At least then all we had to worry about was where the next polaron beam was coming from...": Capt.Hunter, USS Tempest