The wiki explains that most of the crew from this movie is from mainland China, however it was made by a Hong Kong director and was filmed without permission from the government.
It explicitly states
at the time, no mainland Chinese publisher would have published it, nor would the author be safe from government reprisals. Hence, its anonymous publication on the Internet.
The film did had a brief showing run in December 2001, at Peking University, where interest by Chinese citizens was quite high, selling out the showings.