Is China complaining about how it's being handled? The BBC version says they commented on how the infomation released was leading to confusion, and I took that to be a criticism of press handling.
Because the expert and governmental organisations of the nations involved in the search will be sharing far more info than that which has been released, and any perceived deficiencies in that would be handled behind the scenes, not in public statement (especially not by the Chinese).
And releasing bits of info, or having bits emerge from third parties, is causing spikes of media focus, which is probably no helpful, as snippets are continually over-analysed.