Why did Europe go from a poor backwater to an economic and technological powerhouse? A major factor was its lack of any centralized government, and a large number of small competing states.
Secession and decentralization are good for two reasons: they move us toward a society with more individual freedom. And smaller, more decentralized societies are more economically free.
If we regard nationalism as necessarily harmful, we end up supporting the Soviet Union, and every empire and two-bit dictator who manages to hammer together a variety of disparate groups under a single national banner.
States seek to perpetuate themselves by seizing more control of capital and human beings. Size makes this easier. And every regime would become a mega-state like China or the US if it could.
Smaller countries have often been shown to perform better than large countries in terms of overall income and in economic growth. Also, their populations often enjoy more healthy and safe social environments.
If opponents of the current ideological winds blowing in Virginia find themselves in a permanent minority, it may very well be that the only method of defending the minority position is by leaving the state. But "exit" can theoretically be obtained in more than one way.
