Nations have the right and the duty to defend themselves. War, preemptive self-defense, retaliation, or even outright aggression (whether one supports specific acts or not) should not be considered legitimate indicators. In fact, America has been far less violent abroad than other comparable world power at any given stage of their rise to globalism and period of dominance.
Violence we inflict upon others during war, conquest or annexation, or even in self-defense does not necessarily make Americans a violent people. Such violence is the way of the world. All great civilizations, and many not so great civilizations, have participated in such violence. Saying Americans are violent in this regard is saying nothing.
Even if one considers America an expansive empire in the tradition of Persia or Rome or any of the great European colonial powers, as some critics do, its history has not been written in blood in the manner of these empires and most certainly not in the tradition of a Czarist Russia, the Soviet Union, Nazi Germany or Imperial Japan. Any comparisons between America and these nations is not only reprehensibly false, it is misleading and beside the point.
We’ve never harbored a desire for conquest and territorial acquisition strong enough to overcome our deep and pervasive desire to be left to our own devices. Our isolationism has kept us from perpetrating violence upon foreign people than some jingoist elements might have cared to.