I don't understand how modern Vietnamese can see a westerner in their country and not spit on them...

It's cultural, or perhaps civilizational habit, distinguishing between the system and the individuals. Granted it is puzzling for the westies, but there you have it.

Nevertheless, I did find the article astonishing in this instance, confirming the colonial attitudes of Europe. Thankfully resting in the dustbin of history now. Stark lesson for BRICs, which no doubt resonates.