The sports team names that invoked reminders of native Americans arose from respect for native American warriors as brave and fierce. None were an attempt to slight or disparage native Americans. Also, if some called them “Indians” it was out of ignorance and not disrespect (arising from European thinking they had found their way to India when they had only just reached the Americas).
Let's bear in mind that, in terms of anthropology, the Europeans who described the men they found in North and South America as "Indians" were correct--certainly as correct as anyone who describes white folk here today as "Europeans."
Why? We now know that the ancestors of the American Indians all came to our hemisphere over a land "bridge" that once connected present-day Siberia and Alaska. It washed away millennia ago, but the geological and fossilized evidence of the link from both sides and along the ocean floor are irrefutable.
In particular, the evidence includes the fact that our Indians were and are genetically related to the Siberians of the frozen north and to the East Indians of South Asia.
The usual theory is that Columbus didn't realize the world was as big as it is, and had no idea that North and South America were there. He certainly didn't publicly let on that he knew.
There is also another theory, based on how incredibly reliable his geographic and sailing expertise were. After all, he managed to reach the same beach in the Caribbean islands from 4000 miles away in Spain without any modern navigation tools--four times in a row, without losing his way once.
That theory is that Columbus had plenty of information from other navigators in the exploration game, which was a major "industry" at the time. And he was acknowledged as the best navigator. It could be that, reasoning from the earth's geometry and perhaps odd sightings noted by other sailors, he put two and two together and concluded there was a huge, mystery land mass in the middle. But bear in mind that the voyages that could be financed by the "market" of Europe's kings and queens were ones dedicated to finding a quicker route to the hot markets of East Asia.
Considering how rich Columbus and his sons got from income from his discoveries in these "Indies," it could be that he was as crazy as a fox.
Sure sounds like an American.