It is easy to tell the difference
have them over for a beer, hand them a MGD, the beer geek is going to take a slug and the conversation is going be about how the influence of WWII and having to brew for womans taste as men were all overseas created the taste profile of American beers
on the other hand, the beer snob is going to ask if that is all you have and tell you it is nothing better than donkey piss
The beer geek proved that the beer may not be his favorite, but it is beer and he knows why the profile is what it is. He proves his true knowledge of beer and experiences the beer in hand as another example of the vast examples in the world for us all to enjoy.
the beer snob proved is ignorance of beer by deciding that only beers perceived as popular were in his taste experience and that if he was not aware of it, or if he and his crowd did not approve of it, he would not experience it. It was not a matter of if it were around, it was a matter of if he approved.
I remember when I became a beer geek, we went into a bar that had 77 beers on tap, That was unheard of in the day. and they had over 100 beers total. We kept going back till we had tried them all. And I still think I missed a few. Anyway I found beers I love, beers I had only read about in books, beers I did not care for, beers that were just strange, and we drank them all. We loved it. It sent me off on the long journey of beer.
Now I can look back and say, I tired that, because I probably have, I have sought out more types and brands of beers because of the influence that bar had on me. I have hugely enjoyed the experience, AND IF SOMEONE HANDS ME A MGD, I smile, take a long slug off of it, enjoy the cool crisp taste that only a American Premium Lager can supply, and thank God for his gift of beer to us all. After all he may be hiding the Dead Guy Ale for the second round.