Because you still don't understand, on an underlying level, what culture is, how people differ from each other, or how to accommodate that diversity. I'm trying to help you by at least pointing you in the right direction, but I'm close to giving up. It's Dunning-Kruger (which is not an insult and not uncommon in this domain) -- you're unaware of what you don't know.

My experience is the international business community has generally done the best work here, since they needed to create organizations which work across cultures, and that's difficult if all employees take the type of myopic view you're taking. Good starting points include Hofstede, the Culture Shock series, Neurotribes, as well as Googling "[insert-country-name] business culture" (the country should NOT be Western or Southern Europe, which are too similar to the US).

If you choose to go down that route, it will take a few years, but it will make you more successful in your career, and a better person in your personal life.