A poison control expert once remarked that the danger is in the dose, not in the substance. The same holds true for the earthier flavors in wine caused by microbiological growth (other than the yeast that ferments the sugar into alcohol).
For example, wine expert and author of The Wine Bible (aka, The Wine Tome), Karen MacNeil, talks about 'cat piss' flavors in Sauvignon Blanc as a positive characteristic...so long as its not too much of a good thing. At the right levels, microbiological leavings can add to the complexity of wine. When they're too high? Blech.
I think it's safe to say that (in general) the French like earthy smells and flavors more than Americans do. Think about the whole 'French people never take a shower' thing that some people like to complain about. Think about where truffles come from. Remember, it was the French who thought of using a pig to find a fungus and then put it on the table. Think about the fact that the French smoke everywhere. And what about their cheese? French cheese can be extremely stinky, and they love that.
If you need more proof of this concept, note that the cultish marketing guru, Clotaire Rapaille, made this insightful if melodramatic (paraphrased) statement on a PBS Frontline installment called The Persuaders, "In France, the cheese is alive. You never put the cheese in the refrigerator because you don't put your cat in the refrigerator….in America I can tell you, the cheese is dead everywhere…'This cheese is safe, is pasteurized, is wrapped up in plastic…You can put it in the fridge.' I know the fridge is the morgue. That's where you put the dead bodies, eh?"
Eh, indeed. In America, we like our food to be clean (and perhaps a bit more dead). In France, they like it teaming with life: we invented hamburgers, they invented Steak Tartare.
Our taste in wine follows a similar train of thought: we favor clean flavors that come from squeaky clean presses. Modern presses and tanks in Californa are made of stainless steel and housed in concrete buildings with epoxy resin floors and wide drains perfect for hosing down with a solution of TSP (tri-sodium phosphate). They're designed from top to bottom to stop the spread of bacteria and mold from one batch to the next. In France, the presses are fequently smaller, older, maybe made with wood components, and may not even receive a rinse between batches.
One result of this difference in approach is more of the musty and fusty in the wine. Or is it simply more delicious complexity? You decide.