I guess it’s a distinction that i don’t see as important. Florida is part of the United States, and there were slaves in Florida in the 1500s, that they were Spanish slaves, and not British slaves, doesn’t seem that important to me; I don’t blame our country for those slaves, but I don’t think it is important to discount them either. I don’t blame our country for british slaves either, I blame our country for the slaves we allowed as a country.
Which we did not allow for long; although it is hard to give people too much “credit” for ending something that was wrong from the start.
“I guess it’s a distinction that i don’t see as important.”
I’m not aware of any American histories that use Spanish colonies as their starting point. They begin with Jamestown and Plymouth.