The map is obviously ridiculous to begin with so I’m curious why it couldn’t just be a bunch of Foreign Ministry staff having a laugh while flexing their diplomatic muscle a little bit. It’s not like they have many other avenues to counteract growing Chinese geopolitical influence.

Think about the easter eggs found in all manner of serious software put in by engineers for a joke. I think anyone in Vietnam can easily pirate it if they actually want to see the movie so there’s little actual damage, as long as they don’t care about the economic impact at the box office.