You guys need to know...After the 61-74 war here in Viet Nam , things were quite bad for people in the South of Vietnam. After the North took over in 75, they treated the Southerners horribly. They caught and found and picked everything they ate. This is why you see them eating so many unfamiliar ( To Us ) things.. Old habits hard to break....
I'm sure that is a big part. And different cultures just eat different stuff. See many things considered delicacies and would be untouchable by the poor, that I think are just nasty...