They are they, and you are you.

"Asian are not very friendly to each other, they are very friendly to American, but American don't give the same friendliness back, which make me feel very sad.Some American are very rude to Asian."

Just pay no attention to this type of things. The more you pay attention this, the more you feel embarassed, sad, angry and wanting to correct them. At the end, it is none of your business. You should not be judgmental, and you do not need to feel guilty because they are also Asian. They are they, and you are you.