I agree that Islamism probably would've happened no matter what - the seeds were there very early in the 20th. I don't think America would be a target for those groups if not for our own foreign policy.
You've advocated for interventionism on tactical grounds which, I think, is an argument that's undone by the history of our attempted interventions in the past 100 years. I'm not sure why you're bringing Vietnam into this (The Act of Killing covers the slaughter of dissidents in Sumatra, which occurred under a US-backed regime).
The Islamist movement likely wouldn't have grown as big without Operation Ajax, and the anti-American sentiment wouldn't be as strong, but I think it would still be there. Qutb and others have long written of the horrors of secularism in America and Europe, and how they go against fundamental "Islamic values." A confrontation between Islamists and the West would seem to be inevitable.
There is also the case of Israel, which America (and to a lesser extent Europe) has long defended, and even established. Even if the United States hadn't provided support for the Israelis in Six-Day War (though we had been supporting them beforehand, albeit to a lesser extent), the fact that the United States and Western world established Israel in the first-place was a cause of some contention. Though technically the British were initially opposed to the idea, and the Jewish/secular settlers had to fight a bloody war for their own independence from the British and Islamists.
By all means, correct me if I'm wrong, but I think the difference between you and I is that you believe any and all forms of intervention are inherently evil and doomed to fail. I, on the other hand, believe that in a select few cases, intervention is justified and that the end will outweigh the means. We have plenty of examples of successful nation-building, such as Japan and Western Europe following World War II. Or if you want to get more academic, look to Canada (1837), Hawaii (1893), the Philippines (1898), Taiwan (1945), South Korea (1945), Italy (1948), Colombia (1964), Dominican Republic (1965), Grenada (1983), Panama (1989) and the Yugoslav Wars (1990s), to name a few.
I just feel that dismissing interventionism and regime change completely out of hand would be foolish. Just as dismissing peaceful cooperation and negotation out of hand would be foolish. There is no simple fix to every problem in the world, a strategy that works in one situation, may not necessarily work in another; and vice-versa.
I mentioned Vietnam, in response to
Joshua's post.
Twilight Struggle is a really good board game though.
Twilight Struggle is great, should you ever find yourself in or near St. Louis, we'll have to play together.