Sorry, it is a stupid statement. It is a fine opinion.
4E is Dungeons & Dragons. It says so on the label. (Of course, I also believe that Pathfinder is D&D and Labyrinth Lord is D&D and Castles & Crusades is D&D. What it says on the label isn't the only possible criterion, but it certainly counts, otherwise, the only D&D that ever would have existed would be the original LBBs -- certainly there are folks in the OSR community who feel this way.)
It's also Dungeons & Dragons because it honors the sacred cows of D&D -- ENWorld has had multiple threads enumerating the sacred cows, and you'll have a hard time finding many D&Disms that aren't in 4E. Beyond something nebulous like "feel," point to something concrete that 4E is missing that other editions of D&D have in common. Because I have a hard time coming up with it. (And don't say a focus on tactical combat until you've looked at the LBBs, which are only a half-step beyond the Chainmail rules, at best. And if any game is Dungeons & Dragons, it's the set of rules that orignally bore that name.)
He doesn't have to like 4E -- I sold all my 4E books, after all -- but to say it's not D&D as though it were a fact is stupid. To say "I don't like it because of X, Y and Z" is not only better, it's actually helpful, since it lets would-be customers know whether they care about similar criteria. As it is, the sole criterion is "this dude doesn't like it," which doesn't necessarily mean much to anyone.
He didn't say it is not D&D. He said it is not recognizable as D&D. To say, someone who has been playing since the 70s, as he and I have.
The conversation was precipitated around me ordering two Labyrinth Lord, and LL AEC. I have both of them downloaded on my computer in PDF, and they are very recognizable as D&D. I have looked at the Pathfinder rules online, and they are recognizable as D&D. Nearly every conversation I have had with someone about 4E is that it is a different game.
Some like it, some don't. One of the store owner's critique of it was that he played a session in his store, and it took two hours to resolve a simple combat. He runs several games a week in his store, and decided he did not want to run 4E.
Another guy I talked to loves 4E. It is the only version he has played.
The store carries a full line of 4E products, so I doubt he is discouraging people from purchasing it. I was asking about editions, including Pathfinder, and OSR stuff. His opinion was that 3.x still felt like D&D, Pathfinder feels like D&D, but 4E does not. Meaning, feeling like you are playing at least a variation of the same game you've been playing for 30 years or so.
Interestingly, he told me that Lamentation of the Flame Princess has the tightest set of OSR rules he has seen, and they prefer it because of that. They don't play it as "weird fantasy"... just use the rules for their D&D game.
To say that "if any game is D&D its the original books that bore the name" ignores perception of people who have played the game for decades. I owned a couple of those little brown books, but never used them in play. Having already played Basic D&D, and AD&D, those books didn't look much like D&D to me. It may be that a few editions from now, nothing pre 4E will "feel" like D&D to most people, and that for new players who started playing with 4E, nothing else feels like D&D to them now.
As someone who was looking to spend some money, I valued his input. Had I gone in there to buy some 4E books, I doubt he would have scoffed at my purchase.