There are many differences, none of which are dispositive on whether or not attacking Iraq as a battle in the WOIF's was a mistake as this moron you support seems to think. The moron claims that history tells us that killing our enemies and then occupying their country for a time can not have a positive outcome. He uses that in an affort to persuade that the war in Iraq was a mistake. His logic sucks. Entiendes?
The Japanese were faced with us, or death. The Germans were faced with us, or the Soviets (arguably worse than death).
The Iraqis aren't faced with anything but us. Sure, it's a rough neighborhood, but no rougher than it's ever been.
They're glad Saddam is gone, but as irrational and illogical as it clearly is, they don't consider us much of an improvement. So, the factors that made our victory over the Axis possible aren't in play here. The Iraqi people have nothing to lose by resisting us, and as a matter of national pride, have much to gain.
Capiche?