First of all, did you know that when the Pilgrims landed in Massachusetts, there were already two Indians in the area could speak English, despite the fact the nearest English settlement at the time was in Virginia. In fact, one of the two could also speak Spanish, and had spent time in both Spain and England. (By the way, in the link above, note the role of Catholic priests in freeing Indians who Europeans attempted to enslave.)
Secondly, by the time the Pilgrims arrived in Massachusetts, somewhere between 70 and 90% of the coastal Indians had been wiped out by a plague caught from English traders with whom they had brief contact. The European effect on the Native American population is sometimes described as a "genocide." It is certainly true that Europeans often behaved very badly towards the natives. But the vast majority of the killing was done by germs which the Europeans had no idea even existed, and they certainly had no clue that mere contact with them could affect the Indians in such a way. That is a lot different than deliberately shoving people into gas chambers, and to use the same word to describe both events does not seem very helpful.
Thirdly, in discussions of social contract theory, you sometimes see it said that no political society has ever been founded in such a manner. That is just not true: the Pilgrims founded their polity with just such a social contract, namely the Mayflower Compact. I grant the critics of social contract theory that one case out of all polities is not very many, but still, it has happened.