"Forget about the true tragedy which put Israel on the same level as the original terrorists (foreign hit team kills innocent)"
False moral equivalency.
Israel mistook an innocent for a terrorist; terrorists aim for innocents. That's not even remotely "on the same level."
I suspect the people who condemn Israel so roundly for the tragic error are really against the whole concept of hunting down the terrorists and killing them extra-judicially. Israel and its citizens are at war. Those living in the safety of the US may not get it.
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I'll accept that on a morality and intent level. On a practical level the shooting in plain sight in a neutral country can be viewed as similar if not equivelant by the people of that country.