That Honest Abe ,The Great Emancipator-Lincoln created the First Thanksgiving during the U.S. Civil War as a holiday to celebrate the North colonial origination story, to give Union Soldier families something to be thankful for,
...yet Mayflower and 1620 landing on that Rock in Plymouth is a replacement Northern origination story, as it was 13 years after the establishment of
Jamestown, Virginia. The first continuous settlement in what became the English Colonies.
Maybe The Original Republicans wanted to belittle Virginia for seceding,
by bringing that Commonwealth down a few rungs on the historical significance ladder ?