In spite of how libertarianism is often portrayed, it's not a middle ground between conservatism and progressivism. It's not even on the scale with those positions. But during social gatherings libertarians can be a neutral zone between conservative and liberal disagreement.
The silliness of the political right and left is clear to libertarians, yet we have common ground with each, on those few issues where they still support individual liberty. Progressives and conservatives are more similar to each other than they'll admit. Why should they fight over the minor details on which they disagree?
Cousin Xander might believe government should do something which Cousin Yolanda opposes, while Yolanda wants government to do something Xander feels would be the end of civilization. The libertarian in the room knows that neither cousin's wish excuses government violence. Pointing this out can distract the factions from being at each other's throats by giving them a common enemy.
Expressing skepticism about the importance of the issue they value enough to fight over can make them unite against you.
Grandpa Al and Grandpa Bill may revere different presidents and hate the presidents revered by the other. Their libertarian grand-kid can see the flaws of both politicians and the ridiculousness inherent in the office of president. To explain there's no substantive difference between their respective heroes is a sure way to help them forget their disagreement with each other for a moment.
Once you understand that all politics is the search to justify government violence against those who are looking for an excuse to use government violence against you, it's easy to see why politics doesn't belong in society. It also helps you understand why those who are arguing aren't nearly as different as they imagine.
If you find yourself under the boot of government violence you won't care whether it's a right boot or a left boot. Libertarians decry the boot while progressives and conservatives argue over which foot ought to be wearing it. Consistent libertarianism is non-political, which is why the Libertarian Party-- being political-- has such a hard time gaining traction among libertarians.
Personally, I don't think social occasions are any place for politics. Yet politics will crop up in the most devious ways and in the least appropriate places. Having a libertarian in the mix helps unite all the pro-government people against the one who can't embrace their government extremism. It's our sacrifice for the cause of world peace. Happy New Year!
