The PEPP is absolutely correct in pointing out that the drone and FA50 attacks being carried out by the military under Duterte are in violation of human rights and international law because they are indiscriminate attacks against civilian communities and they provoke the escalation of the level of violence between the belligerent forces in the civil war in the Philippines.
The NPA is not entirely helpless. It has already the expertise in making and using explosives. It can learn from the Taliban in Afghanistan, which retaliated against the drone and FA50 attacks of the US by using ground level explosives which are more easily targeted against the reactionary military and political officials and structures. The Taliban ultimately defeated the US and its air power.
Much earlier the Vietnamese people’s army defeated the US and its air power as early as 1969 by bringing down 10,000 US planes of various types in 1969 with the use of portable ground to air missiles.
As a public intellectual, I am just making an observation on the basis of recent history.