Oh come on, it is only Cultural differences than mere social etiquette.
In some Eastern societies, providers of precious food would be dismayed or disappointed if there are no expressions of appreciation of food served. And often, sadly in our history of Humankind, many were slaves or serfs & thus often goes hungry, & when the opportunity to eat good food, their appreciation shows thru NATURAL behavior, to gobble up food.....
To share personal experience, the insignificant nobody me was taught that in Muslim or Arabic culture, one must leave at least a portion of food un-touched, to show to the host or even the hawker stall that one is filled by the kindly gesture of the provider of food....which sadly I often do not follow such custom as either I am very hungry after having no time for meals as I often have busy & hectic schedules or the food is just too good, & would even call for seconds, to heck with customs which fortunately many of my hosts were thankfully not offended but even happy for my appreciation of their food, which I would either pay in return - in cash to food servers or in kind to hosts such as small token gifts in appreciation of their food & kindness.
Equally in Western civilizations, they too experienced such behaviors, even with unhygienic hands, but thanks to their fortunate evolution during the Age of Enlightenment during the 17th century & sciences, they had a headstart & developed better social behaviors, to realize Freedom comes with responsibilities to others sharing the same space.
It will take time for many others to adopt such measures, & thus have patience. Some may criticize the videos provided by the threadstarter, but it is educational to evolve & uplift lives when taken in the right spirit, devoid of ego or nationalism or whatever excuses the petty can come up with, to evolve Humanity....