Lucky me, this is my subject.
There is no question that white people, in general, treated Native Americans like garbage for hundreds of years. The disease that wiped out 90-ish percent of the Native Americans was neither the fault of, nor particularly understood by, Europeans long before they landed or settled in what is now Florida, New Mexico, Virginia, or Massachusetts. That said, almost every white settler certainly took advantage of it, leveraging their social, academic, and technological advances to cheat, swindle, steal from, marginalize, abuse, enslave, or outright massacre Native Americans in stupefying numbers. These only expanded in scope and cruelty as nations were established and armies stampeded west, and there are mountains of historical evidence to support all of that, sometimes literally.
There are, however, exceptions, and the relationship between the Plymouth Colony and the Wampanoag Tribe is one of them. For thirty or so years, the bond between Plymouth under Governor Bradford and the Wampanoags under Massasoit was one of genuine friendship and mutual respect. Even as conflicts such as the Pequot War raging just outside its borders and colonies such as Massachusetts Bay and New Amsterdam grew to impose their will on anyone they could find, these two settlements remained, in many ways, the ideal that people today wish all of European-Native relations had been over two continents and four centuries.
It is therefore totally justifiable for Native Americans and their sympathizers to criticize the actions of the white settlers; even when comparing them only to those of their own time, their actions as a whole were brutal and merciless. To tear down the feast we celebrate at Thanksgiving, however, and the two settlements who attended, is to aim at the wrong target. They were in many ways the only good guys in town.
Thank you for coming to my TED talk.