Forgive me. I get the drift of your arguments now.
Yes, the locals started the civil war. The US did not in a legal sense. I'm not one of the intellectuals who would dream of bringing the US to court for that.
However,
If the US had not invaded, would there have been a civil war? No
If the Bush Administration had actually bothered with some post-war planning, could a civil war have been largely or wholly suppressed? Probably
Did the US destroy the power structure? Yes, by disbanding the army, not simply by removing Saddam. Jay Garner told Bremer that.
In that sense, pragmatically, did the US 'start' the civil war? Yes
Has the Invasion of Iraq made the World a safer place? I doubt it.