Guns are integral to maintaining the Republic and are therefore protected by the U.S. Constitution. Radar detectors are not.
But I agree with you. Radar detectors should be legal. However, the Constitution says that states should make laws of *almost* every sort for themselves. In this case, Virginia made a bad law. But overall, it's far better than New York.
I'll throw you a bone: New York is farther from Washington D.C. than Virginia. That's ONE thing in New York's favor. I'm not sure I can think of another.