It is considered a misnomer because:
1) It does not identify the area in any concrete terms.
2) The name excludes a large portion of the metropolitan area in southeastern Virginia (Williamsburg, Poquoson, York County, Northeast North Carolina, Gloucester, Franklin, Smithfield, Isle of Wight)
3) It doesn't make any sense to say I live in the 7 cities. Really, you live in 7 different places.
Me: Man, that word is so 2000. I'm going to Norfolk.