Talking about wine is great; shit, I fucking love talking wine. I'm just puzzled, not with the fact that everyone seems to have an opinion, but that everyone wants to give you advice, solicited or otherwise. And it's not just wine . . . you can't just talk about things anymore, everyone has to prove how knowledgable, how insightful they are by telling you what you should be drinking, what you should be reading, what you should be doing. Chafes me like nothing else.
Just leave it alone. My goodness, please, unsolicited advice is the worst kind. I'm a bit of a crank, but the woman who was rattling off wines I should be drinking halfway through our conversation was really talking out her ass; I mean she finishes her tasting notes with and it goes well with beef fajitas. If anything, I should be going out of my way to avoid the wines you've suggested, never mind the fact that we were just talking casually about the next Vintages tasting.
I've adopted a few strategies when people start recommending shit that I should do/drink whatever. A few things that always seems to work - just don't plan on, you know, staying friends.
Silently staring, without expression, is effective albeit a bit subtle (and most blowhards are anything but). It also doesn't work unless you're speaking in person with someone. In those situations, a simple I don't recall asking for any advice can be enough. But in my opinion, the most eloquent (and elegant) way to stop someone from spewing unsolicited advice is demonstrated by the great Ron Swanson in 5 crushing words: I know more than you.