You are right, however, about the emboldened. But you aren't recognizing that this is exactly what we are doing today. Europeans created this bad border mess and then simply walked away denying all responsibility. The reason they could walk away was that the technological time in history allowed it and they had another country that would be left holding the bag. Through the Cold War, the U.S. and the Soviets propped up dictators in the name of stability and camp loyalty. After the Berlin Wall came down, both walked away and left the Middle East to fester under those dictators. By 2003, the Middle East was left without the option of sorting out any of their own problems. And unlike the Europeans, the U.S. doesn't have the convenience of passing the bag on to another to hold and to take the blame.
There is no isolationalism anymore. The world is too globalized. In fact, it is so globalized that a disease can cross borders, infect another country, and affect commerce and trade. Bad bank business can wreck the world into financial disaster for years and years. Dictators who have convinced their people that the true enemy lies across the ocean eventually give their population license to breed radicals and extremists until one day New York City blows up. Working out their own problems is exactly the opportunity we have offered. Removing Hussein kicked off the notion of Arab democracy and ended that UN mission that Osama Bin Laden used to justify 9/11. The Arab Spring represents Arab Muslims sorting out their own problems. However, we have to be vigilante of the "Syrias" that threaten trade partners and defense partners and stand to blow up beyond its borders.
Isolationalism = U.S.A. prior to WWI
Imperialism = U.S.A. after WWII until the end of the Cold War.
So what are we doing today when the result is a Muslim civilization getting the opportunity to "work out their own problems?" You state that its not a choice, but war protestors and supporters are constantly preaching exactly that.