As for the point in question here: yes, I know your dim memories of your 3rd grade history textbook is telling you that the first Thanksgiving was a happy union where the nasty Indians who had been capturing hapless Englishmen finally did something nice for once and helped the poor Pilgrims survive a harsh winter, but no, that didn't happen.
The actual history is that the first Thanksgiving feast was called by John Winthrop as a celebratory feast to welcome home the soldiers that had just massacred the entire Pequot tribe, who they'd declared war on because they wanted the land, and used as an excuse the fact that the Pequot had killed a slaver.
The original post on Facebook has been deleted. For the time being it will be unattributed. But it is too good to pass up.
I learned a nicer version in my youth where the Pequots were not savages but recognized the plight of the innocent, distressed Pilgrims and set a feast before them. Somehow Pocahantas was involved in the scene. Not being a history buff by design especially in the third grade, the whitewash I learned remained as a nice fiction for the celebration.
The family and friends dinner with thanksgivings common to all traditions became the focus of the holiday. Almost as many thanksgiving fables were around the tables as there were people so the traditional ones were lost.