Wait a sec...
First of all it's largely a myth that the New Englanders brutally exterminated a huge continent worth of people.The Native Americans were very spread out in small clusters, and most of the American-Indian wars consisted of localized conflicts (think like those westerns where the violence revolves around small groups)
That isn't to excuse when it did happen, and it most certainly did happen, but as stated the Native Americans were concentrated in a few areas and not necessarily just everywhere. Again from wikipedia...
"The United States Census Bureau (1894) provided their estimate of deaths due specifically to war during the 102 years between 1789 and 1891, including 8,500 Indians and 5,000 whites killed in "individual affairs":"
Again, not trying to downplay what happened, just trying to say what happened... a much larger percentage of deaths were due to things like diseases transmitted and stuff like that, is my understanding.
Secondly it sometimes went both ways Native American tribes would fight back and occasionally massacre Americans in rather great and large numbers. For example
https://en.wikipedia...i/Dade_Massacre
Third, why are in invaders in MEA I didn't know if that had necessarily been determined.
In fact it's kind of hard to find historical examples of groups of people who literally went into a continent or country and just started mass murdering everyone there. More likely, they move in, set up a government, etc. In the worst instances, rising tensions do indeed produce relatively sizable massacres and death such as in German East Africa
https://en.wikipedia...amaqua_genocide
However, it's certainly not an automatic element of "colonization," it's more that they often play into other issues such as race and factors that still linger today. Apparently the German government still denies that Herero and Namaqua consituted a "genocide" for instance, likewise the conflict between Native Americans and New Englanders is sometimes used as a basis for "White supremacy" and other bad things, and so issues that arise in "colonization" become sounding boards for a variety of other elements.
In contrast, the Akkadians for instance according to what we know "assimilated" with Sumer, not really colonizing. I've also read similar explanations of the "Aryan invasion" of the Indus Valley. Many saw it as more of a gradual displacement, beginning with people just kind of living in harmony and sharing knowledge and understanding.
There's also cases of colonizers killing each other at times, such as you can find in America a strain of Mormons massacring random men, women, and children of a group of "New Englander/Americans" traveling to California in the Mountain Meadows massacre, ultimately actually trying to pass the blame off on Native Americans (so it's like genocide and racism and a few things mixed together)
https://en.wikipedia...eadows_massacre
TLDR Colonization doesn't really mean anything inherently historically it's often been people moving around and looking for places to live, the interactions with people already living there are often multi-faceted and complex.