Art is reflective. Different members of the audience are going to take away different things. I suppose someone who doesn't necessarily hate the idea of war could feel somewhat validated by both the show and the books. Similar to how Full Metal Jacket and Apocalypse Now have both been latched onto by both pro and anti-war audiences, even though they were made with the intention of being anti-war. On the other hand, if someone watching already opposes war, then they could easily take Game of Thrones as a meditation on the horrors of war and the abhorrent depths people become willing to sink to in their pursuit of power. I didn't see many audience members smiling on account of the Red Wedding,relishing the massacre of Wildlings at Hardhome, cheering on Cersei's destruction of the Sept, or reveling in the carnage or the Battle of the Bastards. People may have been rooting for a certain outcome during these events (Ramsay being defeated, the High Sparrow dying, etc) but the show goes to great lengths to show just how unceremonious and brutal war and violence really are.