Answer:
The most close answer should be "The natives were not legal owners of the land and we were justified in our treatment of them."
Step-by-step explanation:
Since the Tuscarora were struggling to be settled down on a small part of Pensylvannia territory, there was another tribe, which was on a similr situation like them, living on the same area: Pennsylvania Iroquois.
Fearing that they might do an allegiance between themselves, european settlers were very anxious of having more native population on the area so that they might make a riot in order to get bak their lands. That's why they decided to open fire to this native village.
Let me know if you have any questions :D