I don’t know about wine connoisseurs, but I’ve known a few Food Science majors. Food Science people do tests. Some tastings are done in rooms with red light bulbs so that it’s difficult to respond to the color of a food or wine. Some tests are done with the same wine or vodka in different bottles to measure the influence of the bottle on the subjective experience of taste. There is BTW, a lot of influence.
Ann C. Noble developed the Davis Wine Aroma Wheel. If you are sceptical of descriptions such as “hints of pear and chocolate, with citrus overtones”, you have to understand that before the wheel, wine descriptions were much more fanciful. Ann wanted quantifiable and replicable ways to describe a wine. If you couldn’t train a panel of volunteers to reliably identify wines that did or didn’t include the taste/aroma, it wasn’t included.
In the years since the wheel was developed, many of the chemical micro-constituents that produce the various aromas have been identified. The chemicals that produce the bell pepper and garlic aromas are nasty stinky at full concentration. In the lab, they’re triple contained and kept in a refrigerator. At UC Davis, the lab was only allowed to open and use them on weekends. If they did it during the week, nearby buildings would call in gas leaks.
So there is a basis for the descriptions. That doesn’t mean that there can’t be inaccuracies in any particular description, only that there is a basis. People who know, know to check for the typical micro-tastes.