Replace Zombies with Rioters and you get this.

Nothing in this movie gets explained properly, except for that moment in which a former James Bond (literally) mentions the ugly corporation tactics to get control of governments and countries. He mentions that these murderers are "men trying to protect their families", and that sounded to me like a justification for their acts, trying to keep things "just cool" (this after the wife almost get raped and they were even shot by a Tank!)

The Khmer Rouge, Shining Path, and ISIS have these ways to promote themselves as "freedom fighters" but they're nothing but criminal murderers. Hollywood gets hooked by their deceitful baits and, like Antonioni once said, separates violence in two: the one by freedom fighters and the other one by the status quo.

In this case, the filmmakers have replaced Zombies for them in what could have been a horror movie. No wonder the Cambodian government banned this film, after what they went through with the ultra-communist government they had (that really is communism, you right wing nuts).