Not only does the southwest have a strong Spanish influence, but Spain settled on the east coast before the Pilgrims (the oldest settlement is St. Augustine, Florida - not in Massachusetts). Both Florida and Alabama have Spain’s flag from the time in their state flags.
While the Spanish missionaries worked wonders, the French missionaries were more like the Apostles - they often went without protection, and several were martyred in the same manner as most of the original Apostles. While Americans are familiar with New England, many don’t know that New France extended deep down into New York State. St. Isaac Jogues was martyred west of Albany.
The dominant history of the US has been from an “Anglo” perspective.
Immigrants from outside the Anglo places, often “Anglicized” their names.
There was quite simply the best documented history for the Eastern seaboard, it was already in English, the Anglos ran things, so leaving other aspects of history to lesser importance got little argument.
Spain/Mexico’s holdings reached all the way north into what became Wyoming state.
The all American western cowboy, came from he Spanish vaqueros, for herding cattle. Most of the gear, the food on the trail, etc. was mainly Spanish/Mexican origin.
So I take no offense with the Pope’s words at all, even though I can trace my ancestry own to about 1630 in New England.
They teach the history of California in California, but perhaps not so much elsewhere.