But the First Thanksgiving was really an alternate reality of what might have been, and what was a peaceful and mutually beneficial co-exstence between European settlers and First Nation for a lengthy period of early colonial history. The Massachusett Tribe lived in reasonable peace with the European settlers (one recorded battle in 1623 after a bad harvest and poor game prompted the Massachusett t attack Plymouth colony, but were ambushed by Miles Standish who had received warning from his friend Massasoit. Massasoit (himself a leader of the of one of the Massachusetts tribes), Standish and Governor William Bradeford went to great lengths to promote peace and mutual harmony.
This peace lasted about 30 years, until the continuing waves of European colonists drove expansion and brought in an ever larger population of Europeans uninterested in peaceful coexistence with the "native savages." The new generation took what it wanted and subjected local tribes to new treaties until Massasoit's son, Philip, united the local tribes to launch King Philip's War.
So do not snear at the First Thanksgiving. Mourn it's promise of a better world, and celebrate it as a better world that we can create.