"Buffalo Soldiers" is a movie with a message. We know this because the movie begins and ends with a voice over. The soliloquies are meant to tell us that the violence in the movie isn't gratuitous and that the story has an underlying moral that will edify those who sit through this mishmash retelling of such war movies as "From Here to Eternity" and "Platoon." Viewers would do better to rent the originals.
The moral goes something like this: there are the mother fuckers and those who get fucked; and then there are those who fuck the mother fuckers. This insightful observation, of course, is provided to us in a voice-over since director Gregor Jordan, like so many others, lacks the skill to demonstrate it visually within the context of the film.
Joachim Phoenix plays an American soldier stationed at a German army camp as the Berlin wall is being torn down. He's in the army because a judge gave him a choice between it and jail. He cooks cocaine that the MPs sell. When a soldier dies and a toxicology screen shows an alarming level of illegal narcotics, someone is sent to investigate.