The illegal ARVN (southern) soldiers and their allies -- The Americans (and Mai Lai was only one of a number), South Koreans and Thais committed atrocities. The Australian and New Zealand soldiers did not commit any KNOWN attrocities. The American "Phoenix project" killed thousands of civilian Vietnamese suspected of sympathising with the "National Liberation Front of Southern Vietnam" (NLF) and the "People's Army of Vietnam" (PAVN).
The US-backed Cambodian Republican Army and police killed between 12,000-15,000 civilian Vietnamese men, women and children in May 1970 and the ARVN reciprocated over the next two years attacking and killing many civilian Cambodians in provinces next to Vietnam.
Yes, it is ALLEDGED that the PAVN and the NLF, mostly PAVN, killed up to 6,000 during the TET offensive in Hue. They do admit to killing some unknown number of southern government officials, senior soldiers and corrupt landlords during the occupation on Hue.
Yes, the NLF do admit to a number of exexcutions of southern government officials and corrupt landlords over the years, but not to the extent the US government states, or the numbers killed by the US during the Phoenix program. Figures on both sides vary widely.
A former TV news cameraman and journalist with over 30 years in the industry in Australia and Soitheast Asia.
Currently a retired SE Asian historian.