dunno how the anti-french resistance war stacks up against the American war, but the latter had the us dumping cluster bombs, agent orange and napalm on villages, is far more recent, made uninvolved neighbor Laos the most bombed country on earth and still maims and kills people across se Asia to this day (those pesky cluster bombs again!) Not shocking that some people might be more bothered by the more recent experience - people are happier about banh mi than birth defects.

I am also leery of arguing against the expressed opinion of actual Vietnamese people on which they consider to be worse.