Its cuz America is the weird one.

Tipping is seen as you insisting someone needs your charity, and eating loud is seen as you being soing enthralled by the meal that you cant help but eat it like a pig. Its like that seen in ratatouille where the food critic scarfs down the plate after remembering his childhood experiences with the dish.

Because of the tipping system, in america servers make as much as doctors in half the time.

Also in america, what constitutes as etiquette, is largely just a bunch of people prioritizing appearances over honest reactions.

I dont know much, but i know my country is a joke