Initial investigations of the Mỹ Lai operation were undertaken by the 11th Light Infantry Brigade’s commanding officer, Colonel Henderson, under orders from the American Division’s executive officer, Brigadier General George H. Young. Henderson interviewed several soldiers involved in the incident, then issued a written report in late April claiming that some 20 civilians were inadvertently killed during the operation. The Army at this time was still describing the event as a military victory that had resulted in the deaths of 128 enemy combatants.

Six months later, Tom Glen, a 21-year-old soldier of the 11th Light Infantry Brigade, wrote a letter to General Creighton Abrams, the new overall commander of US forces in Vietnam, accusing the American Division (and other units of the US military) of routine and pervasive brutality against Vietnamese civilians.

The letter was detailed and its contents echoed complaints received from other soldiers.

What little difference is there between Brady Manning and Tom Glen?

The difference is that the USA has now become totally brutalised by its many wars.