This is a 1980s movie most likely. I only remember parts of the movie.

In one scene, three POWs were hanging in cages when a cruel (possibly Vietnam commander) shoots one of them in his private parts.

In another scene, one of the POWs is very sick. The commander reiterates that he will help that POW if they sign a document stating that they disagree with the war, and will allow them to go home too. But instead of helping the POW, after they sign the document, he instead poisons the POW.

The other POWs go home after signing the document, but since they signed the document, the military and congress refuse to pay the POWs for the time they were in the prison camp.