Making such statement without having zero understanding of Japnese culture and Japnese people are demeaning toward Japnese people.

You are simply ignoring advise of people lived in Japan for more than decades and advise of Japanese natives. You are enforcing the U.S. culture in Japan. You have no idea that some people in Japan even consider being offered tip an insult.

Hope you won't be stero typical "Ugly American" when you visit Japan.