What role does syncretism play in Loewens re-envisioning of the First Thanksgiving?

This is a quote from the book,this basically answers your question.

I have asked hundreds of college students, ““When was the country we now know as the United States first settled?”” This is a generous way of phrasing the question; surely “we now know as” implies that the original settlement antedated the founding of the United States. I initially believed-certainly I had hoped- that students would suggest 30,000 B.C., or some other pre-Columbian date. They did not. Their consensus answer was “1620.” Obviously, my students’ heads have been filled with America’s origin myth, the story of the first Thanksgiving. Textbooks are among the retailers of this prime legend. Pat of the problem is the word settle. “Settlers” were white, a student once pointed out to me. “Indians” didn’t settle…. As we shall see, however, if Indians hadn’t already settled New England, Europeans would have had a much tougher job of it.”

pg 77

“Starting the story of America’s settlement with the Pilgrims leaves out not only the Indians but also the Spanish. The very first non-Native settlers in the “country we now know as the United States” were African slaves left in South Carolina in 1526 by Spaniards who abandoned a settlement attempt. In 1565 the Spanish massacred the French Protestants who had settled briefly at St. Augustine, Florida, and established their own fort there. Some later Spanish settlers were our first pilgrims, seeking regions new to them to secure religious liberty: these were Spanish Jews, who settled in New Mexico in the late 1500s. Few Americans know that one-third of the United States, from San Francisco to Arkansas to Natchez to Florida, has been Spanish longer than it has been “American,” and that Hispanic Americans lived here before the first ancestor of the Daughters of the American Revolution ever left England.”