Well, to be fair, fantasy is a niche genere, and has never fared all that well with the mainstream. Just by being on this site your by definition what the NYT reviewers would consider "one of those people", even if not a D&D player your probably into things that overlap heavily with that entire streotype... like video games.
Fantasy and science fiction come in waves, and the last big wave we had was back when "Buffy" was big, and now we're seeing stuff like "Game Of Thrones", "The Secret Circle", "Grimm", "Once Upon a Time", and others all hitting TV in a barrage, with GoT being HBO's contribution. Whenever this barrage hits, you find a degree of disdain by the mainstream critics and reviewers who like to go off about waiting for people to get over their latest binge of fixation with "unreality".
To be fair, to the crowd that makes the usual run of sitcoms, crime shows (police or otherwise), mafia flicks, westerns, and other things generally tends to see this kind of programming as an anathema, and prefers to see an enviroment where you see maybe one of these kinds of shows outnumbered by other more "normal" alternatives....
As a result reviewers hired by things like The NYT tend to reflect the normal state of events, and when you see these periods of fantasy programming, they tend to get irritated by the most popular of the bunch, and find themselves alarmingly out of their element.
At this specific moment I think "Game Of Thrones" has enough of a following in the mainstream to be around for a few more years. However I'd imagine that before this decade is over we're going to see a massive backswing to more traditional fare as the mainstream does grow tired of it, and it probably won't be until nearly 2030 that we see another major barrage of this kind of thing.
Or in short, I think GoT is just the target of choice for the ire of those who see the "natural order of things" being so heavily disrupted yet again.