I'm not saying you, personally, aren't well versed in Mac knowledge. Maybe you are, and that's great! But this guy's complaint is pretty valid, across the board, from my experiences with Apple stores. (And for the record, my g/f worked as an Apple Genius in TN for several years, and SHE agrees with me on the current state of things in the Apple retail stores too!)
I can remember when Apple first opened their retail stores, you had a different type of salesperson working there. Sure, some of them weren't overly knowledgeable but they didn't come across as "hipster teens" either. And in most cases, a given store would also have at least one or two older people working there (by that, I mean someone in their 40's or 50's usually) who actually could answer most of the technical questions. Your salespeople were happy to refer you to that person whenever it was needed.
Something gradually changed though, in the mid 2000's, when the iPods started selling by the millions and then the iPhone came along. All of a sudden, a big percentage of customers were just looking for new cases or headphones, or had questions like "How do I hard reset my frozen iPod?", instead of Mac OS X issues. It seems like Apple responded by hiring a younger crowd of "hip" and "pretty people" to work their stores and make sure they kept up a trendy image, instead of a "geeky" one.
These days, I really don't find I get very good help at Apple stores at all. Sure, they have enough clerks around in colored t-shirts who you can speak with, but the experience is usually lacking.
EG. I just bought a new Macbook Pro 17" at my local Apple store, and the guy who helped me (only after I flagged him down because he was busy chatting with fellow co-workers) didn't even seem like he wanted to sell me the product! I asked him if they had a particular configuration in stock, and he kind of blew me off with an answer of, "Yeah... if it's shown on one of our cards on the table, then we sell it." (Not my question, buddy! I wanted you to make sure it was really still in stock!) When I told him I "think I want to go with one of these, then", he just kind of stood around blankly -- not getting a clue that he should go get one from the back room for me at that point! I had to repeat several times that I, indeed, did want to buy one from him right then before he finally offered to go get one. Frankly, it was a weird experience, and only one I could chalk up to him being an inexperienced teen.