I might be better for someone to write to them in Chinese. Is there any sign as to whether they are doing this maliciously or whether they simply don't understand the terms of the license? Are any of the people working on the site known to the Chinese Wikipedia community?
If I say, this is an attempt of the chinese gouvement to "hijack" chinese Wikipedia, than this is my own oppinion and I confess, I have no proof for my suspicion. But there are some evidences:
For one, the site is sponcored from the gouvenment or gouvenment own institutions or companies. At the head of their homepage they confess that they get gouvenmental support: 本维客得到了2003年教育部哲学社会科学研究重大课题攻关项目：博客(Blog)技术及其对组织沟通和社会交流方式的影响研究的支持。(which means: This wiki got support from "2003 ministry of education important project for philosophical and social science: studying of Blog technique and its enhancement of organizational and social communication"). For my own oppinion and experience in the PRC, the formulation can also be read as "... of Blog technique and its enhancement of propaganda".
Second, just to the time when all WikiMedia projects are blocked from mainland China, this copy of Wikipedia named them self in Wiki China and announce itself as the first chinese wiki encyclopedia. I do have the suspect that the two actions are connected.
As for the GFDL. As I mentioned above. These are not some amatuers or startup companies. These are professionals. I think they know quite well what GFDL means. But on the other hand. They can also say: well, GFDL is an american licence, it has no meaning in China. So we don't need to mention it or to obay it.
Ting.