As the central defining issue of the left has become hating cis hetero white males and destroying capital, rather than hating capitalists and seizing capital, Libertarianism has become irrelevant.
Libertarians have responded to irrelevance by becoming evil. Tyler Cowen, who is arguably the primary remaining libetarian blogger, certainly one of them, just published a blog post that he does not care about Aleppo– this is the man who cares deeply that a billion black African Muslims are much worse off in Africa than they would be if they were allowed to come to America to live on welfare and crime and vote for more welfare and more crime, this is the man who is so much more moral than you are that you are worse than Hitler for not caring as much as he does.
We are under no obligation to worry about far away strangers hurting, particularly when they are being hurt by other far away strangers as is usually the case. We are, however, under an obligation to worry about us hurting far away strangers, particularly as if we hurt far away strangers and do not much care, they are morally entitled to defend themselves by killing us.
Aleppo is the result of a failed American effort to overthrow the legitimate and long established government of Syria. To this end, the American government sponsored a bunch of genocidal terrorists who intended to kill every Syrian Alawite and kill or expell every Christian and every Shiite of Palestinian origin. These foreign genocidal terrorists seized a portion of Aleppo, kept the civilian population hostage as human shields, and proceeded to lob mortars and rockets into the rest of Aleppo.
The reckless cruelty of progs in general and the American government in particular, with the extraordinary cheerleading of a mainstream media drunk with the blood of innocents, was steadily leading us towards thermonuclear war with Russia.
And this is the question on which Tyler Cowen decides he will not care.