The troops in "Fortress Singapore" were living the life of colonial masters.
We don't like to remember miles and miles of colonial troops saluting at the side of the road as the Jap general rode in an open car into Singapore city to accept the surrender.
Instead we glorify military defeats like Gallipolli and Dunkirk.
Seppos don't like to remember the disorderly rout in Saigon. They promote the story now that "liberals" stopped them using enough force to win.
Even with a 20:1 advantage, air support and use of massive WMDs in civilian areas, they still can't win when resistance is offered. They can do a turkey shoot, but they got no guts, no moral fibre.