Just one more time, as simply as it can be stated:

In the American (US) dialect of English, "African American" or "Black American" or "Black person" is acceptable. "Blacks" (with an ess) or "the blacks" or "a black" is unacceptable, insulting and demeaning. It means the same as "kaffir". This is as true for non-Black Americans as it is for people of color. We don't use those expressions and it makes our skin crawl to hear them or see them in print. How you speak the language where you come from is your business.