I ask because we Americans, at least, tend to talk about the Germany of the first half of the twentieth century as if it were the world's greatest war-mongering state ever. I'm not questioning that judgment, but I am asking whether Germany of the first World War was - I guess I should say - ethically more of a piece with aggressive acts by other industrial and colonial era European nations than with Germany as led by the Nazis from 1933-1945.
(My apologies if this question is inappropriate to this subreddit or simply not well enough put. This is the question I'd like to have answered, and I can't figure out value-neutral language here. Maybe that's not a problem.)
It's not helpful to lump them together. Germany in World War I nationalistic and militaristic, yes, but so was France and England and Russia. Though occasionally scholarship today tries to be edgy by placing the "blame" of World War I onto one party (often the Germans), most scholars are of the "it was something that was 'going around' in Europe at the time and everybody kind of fell into it." If one was going to make an argument about German exceptionalism, it would be "well the German government was more likely to react based on these feelings (because of its anti-democratic nature or whatever) but everyone had the same feelings."
World War II is really a different question, even though it is logically linked to the results of World War I. The aggression and expansionism was anomalous, the ideology more pernicious, the drive to war less shared. Obviously the Germans were not the only authoritarians (and even fascists) in Europe at that time. And of course one can certainly argue (as some do) that the supposed differences between the Germans and the Allies are not as extreme in many respects as they are often emphasized to be (the British usually get to be the "good guys" in Anglo-American accounts of the war, but their history is more complex, of course).
But lumping together under the banner of "German militarism" creates more confusion than enlightenment, in my view. As with all things there are some commonalities and some differences. But if you're trying to understand why this country was involved in two World Wars, attributing it to some common Germanness doesn't really tell you much. A better explanation, and I think the one much more supported by the historical scholarship, is that World War I was the result of a general problem of nationalism and militarism in Europe, whereas World War II was the consequence of the punitive and unresolved outcomes of World War I. To put it another way, I think we can see Germany's involvement in WWI as "of a piece" with other major trends; their instigation of World War II is much more anomalous and individual.
Scholars will argue about all things, and the literature on "who was at fault in World War I" and "how different were the Nazis" is immense. The above is just a summary of what I think the "center" of that argument looks like, but there are people who would certainly lean towards a variety of alternative approaches. Again, for me the issue is, "what's your goal in either lumping or splitting?" If the goal is to understand the causes of WWI and WWII, I don't think lumping explains much.