Most speakers of minority languages in China are Han Chinese. The censors who interrupted live streams when a non-Mandarin language was spoken were most likely

Most speakers of minority languages in China are Han Chinese. The censors who interrupted live streams when a non-Mandarin language was spoken were most likely speakers of a minority language, just a different one, which is why they didn't understand anything. So I don't think describing it as "Han Supremacism" is accurate. Presumably they didn't interrupt the streams because they felt ethnically superior to the speaker, but because they're liable if something illegal gets said and they don't censor it. And note their reason for not automatically blocking Uyghur content: "We eventually decided not to do it: We didn't have enough Uyghur language data points in our system, and the most popular livestream rooms were already closely monitored." Which I guess means they have a dedicated group of Uyghur speakers on staff to censor those streams.