As I recall about the Plymouth Colony, it was as the Virginia Colony in that certain people decided that they were too important to share the labor for food production. When the crop failure happened and people were starving to death, the Governor made a rule: "No work, no eat." Everyone was given a parcel of land to farm and the crop production was an over abundance of food, so they held a feast to celebrate using the "excess of their bounty," not their larder, not their pantry, but the excess.
Thanksgiving is a celebration of the individual work ethic and effort to produce (work) for the reward of wealth and materiel over collectivism.
The "Pilgrims" were able to farm because Squanto, a Christian Indian went to the colony and helped them. Squanto was abducted by slavers and sold several times before being bought by an Anglican Minister or Abbot and after being baptized he was emancipated and found his way home, only to discover that his entire village and clan died off from disease and illness. Squanto was adopted by another village of a different clan.