It was the United States that blocked that UN visit: https://www.reuters.com/article/us-china-usa-rights/u-s-germany-slam-china-at-u-n-security-council-over-xinjiang-diplomats-idUSKCN1TX2YZ/

Last month the United States, Britain and other western countries objected to a visit by the United Nations counterterrorism chief to Xinjiang, concerned the visit would validate China’s argument that it was tackling terrorism.

Delegates from Muslim countries did visit. From the US’ own propaganda outlet: Arab League Visits China’s Xinjiang Region, Rejects Uyghur Genocide

If your argument were rational and logical then the genocide in Gaza isn’t happening either.

Speaking of rationality & logic, that sentence is sheer nonsense.