This will be a long post, & most probably will be ignored by most. The insignificant nobody me will try to keep it short. Slavery is rather a too strong term to use in this issue.
In Humanity's ancient past, circa 3000BC, slavery was accepted. Innovative leaders found ways for sustainable living for Humankind, to feed all tribes - thru agriculture than hunting animals for food. Agriculture is a laborious task, & need many hands. Thus, thru wars with other tribes over territories, prisoner of wars were found & inducted as slaves. Even back then, our civilized ancestors established codes of conduct towards slaves - their needs were to be taken care off - protection, 3 hot meals a day, shelter, water, clothing, medical care, etc, & after 7 years staying & learning from their captors, to be release to be free, & PROGRESS to take care of their own family after learning from successful cultures.
Unfortunately, our ancestors were only mortals & flawed, corrupted such system & worse still - slaves prefer their sheltered comfort zones & would rather remain as slaves than to venture out & progress Humanity. Thankfully, some did that & thru their freedom - free discussions to find solutions & realization that trade frees all, from a cutting tool to be sharpened to better constructed dwellings, to earn an honest living thru its numerous endeavors, were responsible for the diverse progress we Human Civilization had made today, from being cave dwellers to space faring explorers today.
In this issue, Vietnamese male or female are FELLOW Humans too. Like most Asians whom had for centuries been subjugated by dictators, they lost most of their entrepreneurial & adventurous spirit unlike Europeans whom advanced far earlier. But they know how to survive, as proven by discriminated by the Europeans as 'short & slanty eyed' Japanese during WW2 which saw their demise when lost to them in the early years of war, & lost to the courageous & resourceful Vietnamese in a terrible war that should not had been started, as the Pentagon papers had proven - Uncle Ho Chi Ming respected & wanted USA form of democracy but were foolishly rebuffed by ignorant European centric US administrators in the 60s. They would had been the best of allies & brothers instead of killing each other for 10 long years. Fortunately, the Obama Administration saw the light, ended the enmity, & are trade partners today.
With USA & EU help, Vietnam had progressed over the years, but still have much to go, as it is an agrarian society for centuries & education is limited for most, or the comprehensible need for it. Thus, its industrial & tech skills, as well as production are limited, & subjected to much variations of market instabilities in a free market. It was reported recently that its cottage industry - clothes manufacturing - had retrenched thousands of workers, due to such market fluctuations. to inflation & the insane war caused by RUS in UKR.
Thus, it would be better for the Vietnamese or any fellow Human Worldwide, whom are facing OPPORTUNITY difficulties in homeland, to explore our World for such, start at whatever level of education or skill that can benefit the host country, even at the bottom if need be, but to NEVER look down upon oneself, instead to LEARN & progress up the skill ladder as most of honest & successful Humankind had done so.
White, black, red or yellow, each fellow Human had proven themselves over the past 200yrs that they are capable of achievement when given the opportunity to do so. Only by working TOGETHER will we Humankind progress, evolve & fulfill our destiny to manage the stars, as proven by the small steps we Humankind had achieved since the landing on the Moon in the 60s. FAR more opportunities & resources await us & our generations to come in the stars, than to fight among ourselves for the finite resources of planet Earth....