Unable to cope with the fact that many soldiers didn't feel strongly about winning the war, Major Callicles focuses on what?

He focuses on the My Lai investigation.

Major Callicles' overarching crusade was with what he perceived to be the breakdown of traditional values which undermined professionalism in the Army. His favorite examples included mustaches, long hair and sideburns, prostitution, and marijuana; his goal being eradication of all these scourges. When the My Lai Massacre, cover-up, and investigation became an issue, he focused on that for awhile as another example of his general tirade about the breakdown in discipline in the Army and values in the society, and then returned to his usual anti-sex, drugs, rock & roll, and hair diatribes.