Depends on which Europeans, where, and when. The French had a reputation for peacefully trading with natives and one of the lesser-known issues that sparked the American Revolution was that the English rulers wouldn't allow the American settlers to expand west of the Appalachians, so they wouldn't bother the natives living there.
The first Spanish conquistadors also allied with a bunch of the Aztec's native enemies to take them down. Turns out that capturing people for daily sacrifices makes you unpopular with your neighbors.
Just saying there's way more gray here than most people give the era credit for.