EDIT: assuming that the search functionality works, searching on the usual suspect words turns up nothing of relevance, though one hotel apparently advertised that their service staff were comprised of black people, which seems to be an odd thing to advertise even in 1940. Otherwise, just a few uses of an outdated term to describe a college and someone's stories about (or perhaps written by) black people.
It's known that the industry as a whole was largely segregated at the time, in that most establishments had some kind of "policy" in regard to admitting non-whites -- state or unstated. To an extent such that there were numerous guides published for Black travelers showing where they could stop for the night, just to stay on the safe side.
But still - the title makes a rather bold claim, and I don't see any support for it in the book itself.
I remember the Olds Hotel in Lansing across from the state capital. When I was a teenage newspaper reporter I covered a speech by then candidate Richard Nixon there in 1968. The building is now a State of Michigan office building.