The simple cold itself makes you feel lonesome and since many people don't like the sensation of the cold as it is, people have a natural tendency to avoid the cold. Since Gethen is cold you can tell that there aren't many Gethenyians occupying that area because they would rather stay warm that to possibly freeze to death if they're out in the cold for a long time. As everyone can tell when you're cold you just have the emptiness inside which you can't really seem to shake off, you almost feel very hallow inside as well. Who would even want to be in a place that is always cold either way, even so if a place is very cold its almost natural that it would be isolated due to the fact the for some they can't handle being in the cold. If Gethen is as cold as it says it is I'm surprised hw its not deserted because living in cold conditions is difficult due to not growing crops, maintaining live stock, and having difficulty in finding liquids to consume. To even sustain life in cold conditions is honestly surprising because you don't hear of many people wanting to live in the cold and if they do live in these cold conditions they wouldn't have as many people to communicate with probably due to blizzards  or storms which may pass by and will most likely get buried in their homes which makes it even more difficult to make contact with anyone