A lot of people drink enough wine and care enough about it to know the vineyards, vintages, characteristics of this and that, etc. It's like any other serious hobby, whether it's working on cars, mountain biking, computers/tech, frequent flyering, word maker-upping, philately, etc. You're going to research it and know a lot about it.

I know enough about wines to taste something and decide whether or not I like it (although I also have a fairly wide tolerance), but not enough to say, "I like such and such a wine from such and such vineyard" or "I prefer fruity whatever to buttery whatever else" or "this wine pairs well with this food." I'll know it when I taste it.