Not many years ago, 1987, maybe, the Israeli Defense Forces, moved into Lebanon to intervene in a war between the Christian Phalangists and the Palestine Liberation Front forces.
As they did so, the UN personnel and the PLO combat personnel evacuated by ship, leaving a non-combatant, mostly un-armed population of 1000 Palestinians at the major PLO base at Shatilla, Lebanon.
The Israeli forces moved to surround Shatilla, but didn't enter it. They locked it up so nobody could leave, and brought the Christian Phalangists in to do the dirty work. For 36 hours they lit the sky with flares while the Christians moved in and slaughtered all 1000, every man, woman and child at Shatilla.
A few managed to survive, hiding under the bodies of the dead until the dust settled and the gunfire stopped. Then the Israeli loudspeakers came on. "We are only looking for terrorists. No one else will be harmed. (words to persuade any unlikely survivors to come out with their hands up."
No US president ever became outraged by the slaughter, clearly a military action. Clearly no terrorist act. No wars on THIS terrorism, because the right people were killed by the right people.
We in the US never liked Palestinians. They didn't give up their homes and their land easily enough to suit us when we created the Zionist state of Israel. When they were shoved off into filthy camps in Gaza and elsewhere, they threw rocks at cops and got their ugly pictures in the papers.
The PLO became a leading force among them, dedicated to trying to get the ancestral homeland back by any method. They killed Europeans. Killed some good Americans. Bastards. Their leader dressed the way Jesus must have dressed, dressed the way Matthew, Mark Luke and John probably dressed. Didn't shave often enough.
Let the Christians slaughter them all they want, was the world reaction. They ain't getting their land back. We gave it away, and we wouldn't have done it if we didn't know what was best.
Let the Christians kill them all.
The Lebanese Christian Phalangists did their work at Shatilla, but they ran out of steam. So we had to declare war on terrorists to expand the job.
A holy war with the right people killing the right people.
We've got to do it, because they hate us (gotta wonder why), because of the unprovoked 9/11 attack, because, as luck has it, they're sitting on the oil we need to keep the country running.
And, of course, as everyone knows, they want to destroy us.
(Edited in: I've composed this from memory of the events of the time. Some minor inaccuracies, names of places might be wrong or miss-spelled. But this is a generally accurate description of an actual event as it happened, including the reaction of the world (Europe and the US) during the aftermath.