Precisely that--it's war, and one of the most unflinching, harrowing, brutal portrayals of it in fiction. It's all the ugliest and most cancerous behaviors of humankind given free reign, the abandoning of nobility and virtue in order to dig the knife in and twist it.
Then throw in all the incest, rape, betrayal, mutilation, and abuse that takes place in those places that aren't turned into charnel-house battlefields; all the loss of innocence and lecherous lusting; all the petty backstabbings and small-minded pillaging...
GRRM's characters suffer, but they're on no noble path. The pain they go through warps and embitters them, until what they contribute to the plot is the infliction of further suffering on those few innocents remaining.
There is no redemption in this series. There are no happy endings. There is no overarching heroic journey, message, or commentary on the human condition--unless it is that last, and stating that humans are wretched, foul, ill-fated things. Every virtuous character is betrayed, killed, or succumbs to hatred and bitterness. The only successes are those motivated by the need for revenge, and those triumphs are shallow and taste of ashes.
What sphinx of plascrete and adamantium bashed open their skulls and ate up their brains and imagination? Imperator! Imperator!