I grew up in China. When I was little, there was a time that if a Uyghurs person get on the bus, everybody else on the bus would get off. Even nowadays people tend to get nervous when they see Uyghurs wandering on street.
A seed of distrust and paranoia was sown and was allowed to grow. That does not mean it has any basis in fact.
You should also look at how the Chinese government has oppressed the Uyghurs (and Tibetans and Taiwanese, to name a few).