You mean, that Iraq war which was started to find weapons of mass destruction that never existed, and were known by the US government not to exist?
Got to point out that the French supported the invasion of Afghanistan, which was a legitimate response to 9/11. Invading Iraq was merely Bush and Cheney's way of beating their chest.
I personally think that the French only tried to claim the moral middle ground; it just looked high from where the US was looking.
As for 600,000 people: I call bullshit. The US lost 416,800 total in WWII, of which 183,588 were in the European theatre. By contrast the Soviet Union - who were responsible for the fall of the Third Reich - lost over 10 million, nearly all in Europe. The US/British invasion was timed to take advantage of weakened defences due to the fighting in the Eastern front, and had the goal, not of freeing Europe, but of stopping Russia. Without the US, the French would be speaking, well, French (the USSR never forced their satellite nations to adopt Russian), but would have been aligned with the USSR. Wait, that's how they spent the 70s anyway!
Want to bring World War I into the picture as well? Then add another 116,708 - more than half of which died from the flu due to poor sanitation in US training camps (both in the US and in Europe). Total number of US deaths that could be attributed to "saving France": 300,296 - about half the figure you named. I'm sorry about your grandfather and all; my own grandfather flew with the Australian volunteers in the RAF. But get your figures straight. By contrast, the Commonwealth nations (Great Britain and related countries) lost over 1.7 million between WWI and WWI, most in the European conflict.
Excluding the US civil war, the US military has claimed 447,137 combat deaths since the start of the War of Independence - well short of your 600,000 total.
(figures sourced from wikipedia)