You are mistaken. The US entered the war against Nazi Germany only after Nazi Germany delivered an official declaration of war to the US government.

As for Iraq, you are confusing the first gulf war with the second one. The first gulf war was a result of Iraq having invaded a neighbouring country. The second gulf war was a result of an unprovoked declaration of war by the US against Iraq. Not only was it unprovoked but since then it has been established that the pretense for war used by the US government was entirely fabricated.

It is therefore legitimate and justified to use the second gulf war as an example where the US has behaved in a way that the US government now criticises Russia for in the present conflict with Georgia, hence the accusation of hypocrisy.