Jeff Atwood and co. could never "copy" the StackOverflow community into China. And that's what they would have to do..."copy it to China". I highly doubt they could have done it and maybe this new set of programmers can. What harm is there in providing a community for Chinese programmers to thrive?
Look at all Google's efforts...and they aren't the dominant search engine in China. There is too much belief that if a Western company creates a product that they have implicit rights to world domination with it. I think a fragmented world is interesting and more competitive. If it takes copying to bootstrap that fragmentation, so be it.
Which is basically all the clone is at this point.
I still think your focusing too much on "language" rather than "community".
I'm focused on language because that's the justification being given for cloning web apps. No matter what language you want to deal with, claiming that you can't build a community without entirely cloning another team's web app is asinine.
At this point its more than a clone. He published the source with a permissible license (Apache) on a well adopted platform (django).
StackOverflow gave something to the world with its licensing. The creator of this new product followed the rules and even added the bonus of immediately giving something back to the world.
Your argument was that someone can't take a web app and "copy it to China," yet this is exactly what it is at this point from the perspective of someone using the application. So, according to you now, apparently it can be done as long as the person who "cop[ies] it to China" happens to be on Chinese soil at the time and, unbeknownst to a regular user, builds it using a different web framework and open sources it.
No, in fact your origin implication was the right one: the hard part is building a community and delivering a service customized for market beyond simply changing the language, something that so far has not been done here with this application yet.
I'm not sure what your point is, actually. Cloning successful products is hardly new or even frowned upon. Indeed, the computer you are using is most likely a descendant of a cloned IBM PC. Why argue?