They do, plus it's not "in the middle of the class". Islamic prayer timing are vast, like you have a couple of hours to do the prayers so you can finish them before or after class. Before work, at work (during lunch time) and after work.
It's called "Freedom of Religion"....no matter how much economic prosperity you have, if you don't provide your people the freedoms they require, it won't last long.
Obviously they won't show the parts where these "students" are being made to chant the Chinese national anthem or sing praises to Xi Jinping or being forced to eat pork or being indoctrinated to hate their culture and accept mainstream culture.
There were stories of these "students" being encouraged to sell out their parents by reporting any "bad behavior" of their parents to their "teachers". There are countless other stories out there too, each with the same horrific pattern.