Germany and Japan had both declared war on us; Japan actually attacked us on American soil. Iraq did not declare war on us and did not attack us. (Yeah, but he was looking at us funny).
We are supposedly great liberators of the Iraqis, not conquerors. The Iraqis were supposed to greet us as saviors with flowers and cheers of gratitude, which some actually did do. But when civil disorder ensued, when schools and office buildings were shut, when water became scarce, when jobs became nonexistant, when electricity was shut off, when civilian men, women and children died or were maimed on the streets, when prisoners were tortured, when wedding party celebrants were gunned down, many who cheered became disillusioned and bitter.
I don't think that any major German or Japanese cities were no-go zones months after the national governments surrendered. Germany was occupied by the US, UK, France and Russia. It split into East and West Germany in 1949 and unsplit in 1990.
Not until March 15, 1991 did all four occupiers formally relinquished rights to the reunited Germany.
Japan minded its own business as a strictly isolationist empire until forced by the US to open its borders to trade in 1854. After that, they expanded their borders into China and Russia and occupied Korea and Taiwan as well as several islands. Attacking Pearl Harbor was a big mistake.
We still to this day supply military protection in exchange for their agreement not to have any standing army or navy.