A few points here....

A non-violent movement in Germany during the 30's, had it been of sufficient determination and had it involved enough people, could have prevented Hitler's rise to power in the first place.

A similar non-violent movement in America could have prevented America from going to war in Afghanistan and Iraq.

911 was not an act of war, it was a criminal act by a small group of people who did not represent a government or a sovereign nation.

To attack Afghanistan and Iraq over 911 (and over fictional WMDs in the case of Iraq) was not a rational response to such a criminal attack.

The governments of Afghanistan and Iraq presented no real threat whatsoever to the survival and security of the United States, whereas Hitler's Germany in the late 30's and the 40's did represent a very real threat to the survival of the governments of a great many other nations who ended up fighting him.

Therefore, it is disingenuous to use the example of fighting Hitler for some quasi-justification for invading Iraq and Afghanistan. It's a red herring. To put it less generously, it's doubletalk. There is no real correlation between the one and the other. It is, in fact, America that is presently taking up the role Hitler once did...in this sense: America is practicing imperial aggression by a great power upon smaller nations and with imperial intentions in so doing. Like Hitler in 1939, America has pretended to be defending itself against an outside attack or the threat of an attack. (Hitler claimed that the Poles had attacked Germany first and had committed atrocities against Germans in Poland, and most Germans at the time believed him. They also believed that Communist saboteurs had burned down the Reichstag...their version of a 911 attack. This enabled Hitler to establish emergency powers which were never rescinded, paving the way to a dictatorship.) The Patriot Act was a somewhat similar American government response to 911, but to a lesser extent.