Appointed boundaries

From one man he made all the nations, that they should inhabit the whole earth; and he marked out their appointed times in history and the boundaries of their lands (Act 17:26, NIV).

This verse is interesting in political history and church history because both sides of the segregationist debate appeal to it. Segregationists appeal to the second half while opponents appeal to the first half. But assuming Paul is consistent, both appeals can't be right. 

Let's briefly focus on the segregationist appeal. One basic problem with their appeal is how they arbitrarily freeze one particular period in the history of human geographical distribution. But when was the normative status quo that we should retain or restore? 

In the American context, for instance, is c. 1850 AD the standard of comparison? If so, why that date rather than, say, 1000 AD, or 1000 BC, or 2017 AD? 

Or consider the original setting. This statement was made in the mid-1C. Does that represent the normative status quo? If so, what was the racial composition and distribution, within what become the northern and southern boundaries of the USA, in c. 50 AD? 

Doesn't every period of history reflect God's appointed boundaries for that time and place? It's fluid. But that's because God predestines history, and history is fluid. For a segregationist to cite some period he regards as the golden age, and make that the standard of comparison, has no warrant in his prooftext.