There has never been a war on Gethen. Seriously, not one. Oh sure, they have raids, murders, assassinations, and bar fights here and there, but war? They don't even have a word for it. The reason why is one of The Left Hand of Darkness's mysteries. It's speculated that their lack of pure masculinity could be the cause. While a lack of men is definitely the reason they don't have monster trucks, is it enough to write off war? Does Le Guin seriously believe that women would never wage war? On the other hand, it could be the weather on Gethen. Who'd want to fight a war on a planet like that? Whatever the reason, one thing is for certain: the countries of Karhide and Orgoreyn are gearing up for something. And it sure looks like war.
Open communications with the Ekumen will bring the concept of war to Gethen. Once the thought is in mind, it is only a matter of time before war breaks out.
The Gethenians' violent history shows that their tendencies toward neighborly destruction are the same as any human species.