1. Vanilla is a synonym for "plain" when it's artificial (i.e. the vanillin molecule and nothing else). Actual vanilla is obviously a whole different beast.
2. If people who liked wine had such dead tastes buds or (more realistically) noses, why would they bother to make up such elaborate flavors? (In particular, if it were only about status-signaling, the move from old-style wine description ("insouciant but never trite") to the new style ("cassis, clove and cinnamon with a whiff of tobacco and old leather") seems very strange.)
3. My personal experience in general doesn't jive with your theory, except for one point: people who like alcohol tend to have a high tolerance for bitter things, and therefore also like very dark chocolate (I personally am an exception to this, however).
4. ETA: the software converted my 0-indexed list to a 1-indexing. How sad.

You seem to have stumbled onto the existence of supertasters. As a supertaster myself, I find tonic water extremely bitter, must overly sweeten my coffee and can't stand grapefruit juice or spinach. I delight in the sharp sting of a good beer, though. Conversely, there are "nontasters" who have a greater tolerance for strong tastes.

I'm afraid that doesn't mesh well with my experiences. I would actually suspect the opposite; it seems like people who "don't like wine" are missing the nuances between different wine flavors and so I would have guessed they have a worse sense of taste.

For reference, I like some alcohol, do not like lots of salt, and sometimes take violent offense to calling vanilla 'plain'.