We should all periodically revisit the best books and films on the Holocaust, however unpleasant, to keep our own awareness, watchfulness, and revulsion very much alive. There is no shortage of worthy choices.
For a movie like Predators, you don't need a deep script -- just one that understands how to make people laugh when it's not making them scream. Unfortunately, Predators doesn't do much with any of those elements.
Great activist movies portray the ongoing struggle between the welfare of working people and larger societal forces, seemingly beyond their control, that threaten their integrity, livelihood, and often, their very survival.