Well, in the cases I have heard of the money was stolen from the Chinese people so it seems understandable that they want it back.
Also, Chinese are not prevented from leaving the country, que the opposite. Enormous efforts have been spent in sending a lot of student abroad and bringing foreign teachers in (I have been one of them). The thing is for most people here not being able to Facebook is of minor importance compared to access to cheap and good food, secure cities and an environment where they don't feel people look down on them. So, many Chinese students come back to China after abroad studies, despite all the problems in China, and amongst them GFW is the last important.
Also, Chinese are not prevented from leaving the country, que the opposite. Enormous efforts have been spent in sending a lot of student abroad and bringing foreign teachers in (I have been one of them). The thing is for most people here not being able to Facebook is of minor importance compared to access to cheap and good food, secure cities and an environment where they don't feel people look down on them. So, many Chinese students come back to China after abroad studies, despite all the problems in China, and amongst them GFW is the last important.