I think it's reasonable to focus on history through one's own lens, but...well, I'll put it this way. At one end of the historical spectrum there's whataboutism, and at the other, there's myopia. By the tenets of the former, in this context, any invasion in history could be dismissed as "well, what about X?" By the tenets of the latter, any particular incident/region/group in history could be regarded as being unique, damn global context.
Since we're looking at the Americas, you could dismiss the Spanish invasion of the Aztecs by pointing out that the Aztecs were expansionist themselves, and the only reason Cortez succeeded was that he was able to enlist the help of native tribes who were fed up with their masters. It doesn't wash the conquisitors of their guilt, but it's important to note that the Aztecs weren't pacifists either. The whataboutery position can be used to alleviate the conquisitors of any guilt. The myopic position is to regard them as being uniquely bloodthirsty.
The TL, DR version is that if we look at the last 13,000 years, there's been no shortage of conquests, wars, empires, and all that fun stuff. It's why I'm generally wary of people idealizing the past, or insisting that anarchism is the way to go. The entire human race was effectively anarchists before the advent of agriculture. How do you think they fared against agricultural civilization? And how would agricultural civilization fare against industrial civilization? And how would industrial civilization fare against atomic civilization? Chances are, you don't need to play the Civilization series to imagine it, since we've got examples of all those things bar atomic.
USA
