Your most important point deals with a general failure of people to define clearly what they mean by the term "civil war." Almost a thousand days into this civil war in Iraq, and we still have only a few Americans — such as yourself and retired Army General William Odom, to take only two examples — willing to point out this glaring deficiency. I’ve had it out with Professor Juan Cole in e-mails over this issue, since — at least until recently — he refused to see a "real" civil war in Iraq because no large-scale clashes between rival armies, like "Gettysburg" or "Antietam" (my examples), had yet taken place. General Odom, on the other hand simply sees "Iraqis fighting Iraqis" (as you also say) for power and rescources; a fight that began almost immediately after we knocked over the political, economic, social, and military order in Iraq: thereby creating a predictable power vacuum that we could not fill. Iraqis now fight openly — as they have for almost a thousand days now — to fill it. Civil War.
As others in this discussion have pointed out, America doesn’t want to face the terrible situation it created in Iraq. The failure to "call a spade a spade," so to speak, derives from the fact that America wanted to create a deck of hearts and flowers, hasn’t done so, and now refuses to see all the spades busy at work digging graves — for both Iraqis and Americans in Iraq. The psychologists call this "denial." The American government (currently under Republican Party mismanagement) fairly reeks of it.
The Vietnamese Civil War (at least the Second Indochina version of it), became an American War on Vietnam with the introduction into that domestic conflict of America’s Lunatic Leviathan military: driven insane by its own internal political and interservice bureaucratic rivalries for ever-expanding "roles" to play in wreaking havoc on a tiny but ancient country it did not even remotely comprehend. Frances Fitzgerald called it "an Orwellian Army that knew everything about weapons and tactics but did not know where it was." Now, as then, the American Orwellian Army knows all about bombing houses ("safe" or otherwise) but doesn’t recognize the cultural-social-political landscape it inhabits — so it continues to blindly thrash about in frustration, wrecking the joint and hurting itself in the process.
The American War on Iraq will revert to the more basic, lower-level Iraqi Civil War once America leaves Iraq and stops serving as the self-appointed and self-financing (not even hired!) gun for the Shiite-Kurdish Alliance. Then, like when the Vietnamese resumed their own interrupted civil war after the Americans left Vietnam, someone will "win" (or even call off the fight) and the Iraqi Civil War America started will quickly conclude.
As far as I can tell, the American government doesn’t want to militarily withdraw from Iraq because it doesn’t want one (or some combination) of the Iraqi factions to "win." I suspect that the American government fears — with good reason — that its favored faction (or combination thereof) might just take off its pants and run off in its undershorts like Melvin Laird’s "almost-stood-up-until-we-betrayed-them (after 20 years)" Vietnamese faction-du-jour thirty-five years ago. How embarrassing.
The current American government just doesn’t want to face the hideous embarrassment of watching Iraq and its neighbors figure out for themselves how they want to live in their own neighborhood. It doesn’t have to get any more complicated than that. If it does get more complicated, that only fogs the issues and postpones the inevitable day when, as Frances Fitzgerald said, the American government has to face its worst nightmare: "confronting the consequences of peace."