see how 25 years of open trade has done for religious freedom!!!
expect the same in Cuba.
The Chinese have had problems in the past with the Uyghurs; a Turkic muslim ethnic group in China and environ. I’m betting those are the ones the Chinese are most concerned about and do not want them to be further influenced by other Islamics of ISIS and AQ coming in from “the West”.
https://en.wikipedia.org/wiki/Uyghurs