I found this to be a decent enough primer: https://medium.com/@bobbyarlan/a-case-study-in-racist-anti-chinese-sentiment-fuelled-by-american-bots-and-western-propaganda-f0a69978d568

A decent TLDR: The article argues that anti-Chinese propaganda spread by the U.S. and Western media is fueling racist sentiment. Claims of mass detention of Uyghurs are based on flawed studies and sources like Adrian Zenz, a far-right Christian fundamentalist. Atrocity propaganda is a common tactic used by the U.S. to justify wars. The U.S. is threatened by China's economic rise and technological progress, so it is trying to portray China negatively and prepare public opinion for a potential conflict. However, most of the world sees China positively and as an economic opportunity, making a new Cold War against China unlikely to succeed

In short, a lot of information about China that has come out of Western news media has been proven to be based on known biased sources, known anit-China rhetoric, and/or outright lies. It's difficult to prove/disprove of any information specifically, that takes time and reporting, but a lot of people see the anti-China pattern in BBC reporting, and tend to dismiss it because of known history.