I think that libertarian's dogged defense of open borders has been disastrous for the movement. I can understand why you'd hold this position for ideological reasons and want the government out of the process, but it just isn't feasible and leads to disaster. Open borders and the unchecked migration of third worlders means death to civlizations. It's really that simple. It is, by far, the greatest threat that the West faces, and most libertarians have put their stake on the side that's very clearly wrong and joined hands with destructive leftists.
The damage that this has caused to libertarianism is twofold. With the left in every country growing more authoritarian every year, especially the young left, we should seek to court rightwingers, who are naturally attracted to our ideas. Instead, on the most critical issue for young white men, who supported trump recently at 80%, we've given them the middle finger. It's beyond asinine. Secondly, the people that are being imported to our lands will never have any interest in liberty. Their brains can't even properly process such abstractions. The movement's really doing its best to import perma-leftist political enemies.
Pro-open borders libertarians are underming the cause with their stubborness and helping to create a far less free future. They need to be made to see reason or be sidelined.