Jumping on the "realism" statement and applying a very narrow definition of the term is a good way to cut down the argument -- trollish or not -- without actually facing it. i think what the OP is talking about is an issue of tone and playstyle inherent in the system -- one that has changed over the years between and within the various editions. The most obvious cue is the art direction of each edition.
(I am going to leave OD&D and B/XD&D out of the argument. The former because I am not familiar with it; the latter because it is an animal all its own and not part of the 1e-2e-3e-4e continuum.)
1E art, particularly in the early days, was at time crude, and at times joking, but generally speaking had a much grittier, dark ages feel to it. The warriors are wearing hemets and mail and using shields. The wizards, robes and pointed hats. People rode horses, roofs were thatched, and monsters were mean ugly suckers. the art fit the tone of the game very well. 1E was a tough game, as much a test of the player as the PC, with disease and insanity and starvation right there in the DMG next to more fantastical dangers. 1E was "realistic" in the sense that it tried to embrace the dark ages/medieval world (or at least a romanticized version thereof) and challenges. Fantasy elements were assumed to be a little removed from the common populace so that "historical" modes of government and society could reasonably exist in the worlds of D&D -- much in the same way that such elements were fringe in Howard and Tolkien.
By the time 2E came along, the art style had evolved to be generally in line with the covers of your typical high fantasy novels. At least early on, the art was realistic but overly clean and romantic, and the game followed suit. Gone were the rules for starvation, as were the assassin and barbarian. The greys were bled out of the world and high adventure and epic tales were the order of the day. "Real world" threats were pushed aside while monsters and magic became far more powerful and common. Heroism, not mercenary greed, was the assumed motivation behind PC action -- and heroes don't die from rot grubs or disentary (sp), or so we're told. Whitewashed pastiche's of Tolkien and Howard (mostly the former, though Drizzt is well within the sword and sorcery heroic mould) were the order of the day -- many of which were published by TSR itself.
The next shift actually took place before 3E appeared. In the latter half of 2E's life, the "cool" started to take over. There was the Goth-Cool (Ravenloft) and the Punk-Cool (Planescape) and the Grunge-Cool (Dark Sun), but they were all cool. With the possible exception of Ravenloft, the new worlds from TSR -- including, in addition to those mentioned, Spelljammer, Red Steel and Birthright -- took cool to a new level with races, classes, magic and monsters that were an order of magnitude cooler than the previous edition-and-a-half's.
With 3E, we got yet another redesign on the art front, but one that relied heavily on the "cool" of the end of 2E. The rules and implied setting also became "cooler" and less "realistic", finally putting the nail in the coffin of any threats to life and happiness that weren't CR'd. 3.5 and Eberron were the ultimate expression of the state of the art of what D&D had morphed into -- a world so diametrically opposed to the origins of the game that it was barely recognizable as "medieval fantasy" and was often confused with "steam punk".
Now, I have contended in the past -- and will forever, I suppose -- that each edition is in fact a different game, because each one makes different assumptions, suggests a different playstyle and asks different things of the players and DM. And that's fine. the games (and the gamers) can co-exist. I know that i have finally realized that 3.x is not, in fact, the D&D for me, so I will be going back to a previous version. But that I realize that i dont like 3.x, doesn't make it bad or poorly designed (quite the contrary, for its intended purpose, it is very well designed). And I expect 4e to be the pinnacle of game design (seriously; no snark there) by some of the best designers in the industry. But I doubt very much, based on what we've heard so far, that it is going to be D&D to me.
So cut the OP some slack, huh? Even if he was trolling, that doesn't mean he was wrong.