In short, it is the dirt and grit and sex and horrors that the characters endure. We have been conditioned to believe that that and that alone is real. As I said before, the actual Middle Ages (upon which the book that inspired this little meditation is at least partly based) were absolutely nothing like the world presented in this book. Even without the dragons or ice zombies, they couldn't be more different, for Martin has removed everything that was good about the Middle Ages from his world. And for that we call his work 'realistic'.
The problem has been around for some time. Back when I was in the Creative Writing program at university, we would have would be writers bringing in their works about dysfunctional families, meaningless sex, the pointlessness of absolutely everything, who would declare their writing to be a revelation of deepest reality. "This ain't no f------ Brady Bunch!" one drug addled nihilist screamed out in class once. "This is gritty, s-----, punch in the face boot to the head LIFE, man!" as though that was the sum total of life. Happy families are an illusion, miserable ones are real. Also, vulgarities were an infallible touchstone of the real. Polite conversation was a mere social convention and therefore an illusion.
It is an old problem, and, as is the case with old problems, someone else summed it up long before and far better than I could. In this case, CS Lewis in his Screwtape Letters:
You will notice that we have got them completely fogged about the meaning of the word “real”. they tell each other, of some great spiritual experience, “All that really happened was that you heard some music in a lighted building”; here “real” means the bare physical facts, separated from the other elements in the experience they actually had. on the other hand, they will also say “It’s all very well discussing that high dive as you sit here in an armchair, but wait till you get up there and see what it’s really like”: here “real” is being used in the opposite sense to mean, not the physical facts (which they know already while discussing the matter in armchairs) but the emotional effect those facts will have on a human consciousness. either application of the word could be defended; but our business is to keep the two going at once so that the emotional value of the word “real” can be placed now on one side of the account, now on the other, as it happens to suit us. the general rule which we have now pretty well established among them is that in all experiences which can make them happier or better only the physical facts are “real” while the spiritual elements are “subjective”; in all experiences which can discourage or corrupt them the spiritual elements are the main reality and to ignore them is to be an escapist. thus in birth the blood and pain are “real”, the rejoicing a mere subjective point of view; in death, the terror and ugliness reveal what death “really means”. the hatefulness of a hated person is “real” — in hatred you see men as they are, you are disillusioned; but the loveliness of a loved person is merely a subjective haze concealing a “real” core of sexual appetite or economic association. Wars and poverty are “really” horrible; peace and plenty are mere physical facts about which men happen to have certain sentiments. the creatures are always accusing one another of wanting “to eat the cake and have it”; but thanks to our labours they are more often in the predicament of paying for the cake and not eating it.
Where did this come from? I am uncertain. The art following the First World War exhibits this tendency. Perhaps the news also has a hand in this. Ordinary life is simply not news. Horrible things are. A man who works hard and supports his family and loves his children is not news. One who beats and rapes his children is. The one will not have his name recorded for his deeds nor his life examined. The other will.
But this is folly. It is though we were to say that only foul weather is real, and fair weather an illusion. Or that foul smelling excrement is real, but the food that nourishes and sustains and sometimes delight us is not.
That we consider one to be real and the other not, or only the terrible to be real says more of us than it does of our world and, well, anything around us. That we would find a tale of a bunch of coward, liars, murderers and cheaters to be real, but tales of heroism, courage and honour to be fictions is an indictment of ourselves.