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.