Well yeah, it happened. But the CIA perspective is of course "haha we did this thing where we spooked people with superstition" where what actually happened was "we murdered people and dumped their bodies in sympathetic villages and that terrified people and stopped them from supporting the rebels." Like why would "vampires" decrease support for rebels? I doubt people thought the Aswang or whatever just hated rebel guerillas. That's just the CIA psychopath explanation. Yeah turns out murdering people and marking people for death makes people's self-preservation kick in.