Let me restate.
Inside the national border my government has a duty to protect me. Outside of the national border my government has no such duty. But if it chooses to protect me, it is justified in using unlimited force.
There are two issues here.
(1) Is retaliatory use of force justified across national border? The answer is clearly yes, regardless of whether the victim retaliates himself, commissions other private parties, or commissions the government.
(2) Is the government justified in acting on a private citizen's request? To answer that we need to look into the nature of the harm done to the citizen, -- there is no single answer. When government inaction would prompt further violence -- as it would if our government doesn't respond to the terrorist attack -- then the government not only may retaliate, but also must retaliate. When the action would be bailing out a private commercial interest -- such as when Exxon's property is nationalized somewhere -- then the government should not use the taxpayers' money and put lives in danger by retaliating, although it still may retaliate. Looking back at the past 50 years I, together with Peikoff, think that the retreat by the West from the imperialist or colonialist positions it once held,-- such as the cedig of the oil interests, -- was a strategic mistake not because it victimized Exxon, but because that retreat planted the seeds of today's misery in Africa and Asia, as well as the Twin Center massacre.
With respect to some Arab countries we may have a situation when a military action is justified because of 9/11. So the dilemma arises: if retaliation is justified by one reason, terrorism, -- can the government take care of another injustice and repossess the oil company properties at the same time? The answer is yes, because the government has the opportunity to retaliate for the acts of terror and repossess the goods at no additional cost.
And yet you go on to equate apples and oranges. It is never ok to retaliate on foreign soil with the taxpayer-funded military for the advantage or protection of a single citizen.
Retaliating on foreign soil with a military action for terrorist acts is debatable regarding its efficacy. But an action which is born from a desire to protect the nation from terrorist acts is not acting merely on the behalf of a private individual.
Going to war because an oil company's property has been confiscated in another country is clearly not based on libertarian values.
Not even close.