It's a shit take but so is "the French surrender immediately".

The French soldiers had a pretty impressive track record and fought well in WWII. French military planning used outdated strategies, though, and let the Germans encircle them to the point where evacuating the Allied soldiers to England was the last reasonable choice. And the French still managed to hold off the Germans for long enough to evacuate 300,000 men. The rest went quickly because it's hard to fight a war when you just had to evacuate most of your soldiers. Without their equipment.

Likewise, the USA had a decent military track record and well-equipped professional soldiers. But that didn't mean shit when they were (from the NV perspective) the bad guys in an anticolonial war of liberation with broad support from the civilian population. Vietnam was a guerilla war, to which there was no good doctrinal answer back then. And even today those are hard to deal with.

So yeah, "the French surrender when they see the enemy" is on the same level as "the US Army can't stand against the military might of a bunch of rice farmers".