The only two countries with significant Muslim populations that have voted at the UN to condemn China's treatment of Uyghurs are in Europe: Albania, Bosnia and Herzegovina. Both are also currently NATO members or in the process of joining.
All other Muslim countries have consistently voted in support of China's treatment of Uyghurs.
https://en.wikipedia.org/wiki/International_reactions_to_the_persecution_of_Uyghurs_in_China#Joint_letters_at_the_United_Nations
[ Click "Show" to see the full list of countries and their votes ]
The Organisation of Islamic Cooperation (OIC) visited China as part of a greater investigation into the treatment of Muslims in non-OIC member states. On 1 March 2019, OIC produced a document which "commends the efforts of the People's Republic of China in providing care to its Muslim citizens." A coalition of American Muslim groups criticized the OIC's decision and accused member states of being influenced by Chinese power. The groups included the Council on American-Islamic Relations.
After Palestinian ambassador to China Fariz Mehdawi [ar] visited Xinjiang in March 2021, he remarked on Chinese state media that he was impressed by the region's infrastructure and upkeep of mosques,[166] saying "if you have to calculate it all, it's something like 2,000 inhabitants for one mosque. This ratio, we don't have it in our country. It's not available anywhere."[167] RFA journalist Shohret Hoshur wrote in response that Mehdawi was neglecting the harsh reality of locals with whom he had met and who had no ability to speak the truth under the watch of officials, adding that his true motivation seemed to be a shared anti-US agenda with China.[154]
[167] https://web.archive.org/web/20241226072827/https://www.workers.org/2023/06/71505/
