Based on the description of the video directly dealing with Vietnam and the darker aspects to the 1960s, they’re more likely talking about atrocities committed by Americans claimed by the so-called “free press”.
They never discuss the atrocities committed by North Vietnamese Communists when the US pulled out.
Their “anti-war” activists posing on Viet Cong anti-aircraft guns (aimed at our troops) and flying the North Vietnamese flag reveals the lie that they were “anti-war”. They didn’t want both sides to lay down their arms, they were pro-Communist protesters advocating for North Vietnamese military victory. Not a lick of anti-war sentiment in their foul bodies.