Consider the following scenario. A group of Irish republican terrorists carries out a bombing raid in London. People are killed and wounded. The group escapes, first to Ireland, then to the US, where they disappear into the sympathetic hinterland of a country where IRA leaders have in the past been welcomed at the White House. Britain cannot extradite them, because of the gross imbalance of the relevant treaty. So far, this seems plausible enough.
But now imagine that the British government, seeing the murderers escape justice, sends an aircraft carrier (always supposing we've still got any) to the Nova Scotia coast. From there, unannounced, two helicopters fly in under the radar to the Boston suburb where the terrorists are holed up. They carry out a daring raid, killing the (unarmed) leaders and making their escape. Westminster celebrates; Washington is furious.
What's the difference between this and the recent events in Pakistan? Answer: American exceptionalism. America is subject to different rules to the rest of the world. By what right? Who says?
Consider another fictive scenario. Gangsters are preying on a small mid-western town. The sheriff and his deputies are spineless; law and order have failed. So the hero puts on a mask, acts "extra-legally", performs the necessary redemptive violence and returns to ordinary life, earning the undying gratitude of the local townsfolk, sheriff included...
The difference between these scenarios and real life is that 'Merika and the Kingdom are owned by overlapping co-operating corporate baronies.
Given the first scenario, as long as the IRA doesn't touch North Sea oil or any other moneymaking enterprise, they'll be no such objection or need.
A Lone Ranger or Robin Hood figure threatening the money flow of the gangsters that run things in the current environment would be labeled a criminal terrorist, quickly found out by the surveillance state, and eliminated.
Because that's how Consumers are protected in the Free Market.