Mindanao was originally two independent sultanates and was forcibly jointed to the Spanish Philippines. They attempted to reassert their independence when the US took control of the islands after the Spanish-American War during which I believe some 100,000 Moros were killed.
Ok, so just to make sure I'm understanding your on this one, the justification for their attacks on non-US people in the Philippines is this?
http://en.wikipedia.org/wiki/Philippine–American_War
If we rationalized all violent attacks from one party against another, based on previous wrongs that occurred as far back as 1890's, this world would be a very violent place.
If a French person strapped a bomb to themselves and blew up a German government building in present day, and used the excuse that it was disgruntlement from the German Occupation of France during WW2, would you be using this same sort of logic to justify that behavior?
Also, to put things in perspective, Japan occupied the Philippines more recently then we did...in fact, 40 years after we did. And the Japanese Occupation resulted in 4-5x the deaths that ours did. (especially considering that most of the deaths that happened during our occupation were from starvation and not from our bullets). It was the allied forces who went in and ended the brutal Japanese Occupation. (and Immediately afterwards signed the Act giving the Philippines full Autonomy). Of course, during this, the Moros decided just to start shooting at everyone. (Us, Japanese, other Filipinos). The casualty count was particularly high due to the fact that the Japanese and Moros refused to abide by rules of war that state that you don't shoot at Medics.
With all that being considered...shouldn't their anger be directed at either their initial occupiers (Spain), or the people who occupied them after we left and then killed almost a million people (Japan)?
In looking at the 3 foreign powers that were involved, US was neither the first, nor the worst...so why is it our role in the conflict that's getting the blame for radical behavior in present day?