I'm an American living in the Philippines. The dangerous areas are dangerous for all foreigners. Kidnappings are a method for making money. The kidnappers don't care what nationality you are, they're only interested in what funds they could get from snagging you.

There are lots of other areas which aren't considered dangerous, but places in which you could still run across rebel groups. They are the same smiling locals you'll find anywhere else, just with guns and a cause. Flip them some coin for the revolution, maybe buy a bottle of Tanduay and you'll be fine.