First they try to ban digital currency because in first I think they were also afraid on its sudden growth and some business in China will be affected by this decentralized thing that people can earn without paying tax and without working outside their house and I believe if almost of the people in China will be working in home mining and making trading, so I think they put a little barrier for the people to be on their usual self and work.
No offense but their is possible like this, imagine how many people already left their work and decided just to be at home and do bitcoin?