Some aspects are explainable, e.g. limestone-rich soil increases the acidity of grapes, which can impart notes of citrus on the wine. But what about notes of chocolate, or berries, or stone fruit? In some cases, this is totally because the winemaker actually conditions with those things, but in plenty of cases, this is actually imparted by the growing conditions.
For what it's worth, the impression I get is that Americans place a lot of stock in the varietal of grape, e.g. Pinot noir or Chardonnay, whereas the French place a lot more emphasis in the region, e.g. Bordeaux or Burgundy. Both impart different qualities (e.g. it's going to be a lot easier to find notes of pepper in a Tempranillo than in a Chardonnay).