There was a tremendous amount of conflict in the new world, just mostly not between countries (the conquest of the Americas had a death toll of 70-100m people).
Sure but those are relatively few events (though large in magnitude) compared to stuff that was going on in europe/asia. And americas are fucking huge compared to europe and coastal east asia. Turns out when lota people are sandwiched in tight geography, competing for resources for thousands of years a lot of stuff happens!