Go read about the mccarthy era, the red scare before that or the yellow peril before that. Or go read about how how china and the chinese were viewed pre-1970 to how the media changed perceptions during the 1970s with deng's visit, etc as they prepared to open trade relations. Read about how chinatowns historically were stereotyped as the worst kind of ghetto with drugs, crime, etc by the media for much of history. During the 1970s, the media turned chinatown from a ghetto to a hip ethnic enclave.
The same thing with the natives, blacks, mexicans, japanese, germans, russians, chinese, italians, catholics, irish, jews, etc in the US. There were periods where they were demonized and then some switched got flipped and the media softened or completely reversed their stance. Why and at whose request, who knows.
Go look at sino-soviet relations. They are "best buds" and their respective media praised each other. Things go sour and the media pushes anti-sino and anti-russo rhetoric. Same thing with sino-american relations. The interests of the ruling class determine what perceptions the media creates.
Remember when Bush looked into putin's eye and saw a good man? The media was praising putin for stabilizing russia and improving living conditions? It was only 15 years ago, but in media terms, it feels like a lifetime ago. How things quickly change.