Well, don't forget that China , herself, also signed a FTA agreement with Australia. In the end of the day, its all about taking into account a larger market share, which increases dividends. You have to think about business , not so much about cultural purity, my friend.
We live in a globalized society.
In this case should Sudan, China and Chile join the European Free Trade Area? There's a difference between signing a regional or bilateral FTA (something everywhere but East Asia has done) and including irrelevant countries to act as monitors and spoilers of a reasonable deal. Hopefully the CJK will go through at least, as pretty much everyone on all sides wants it.
Just don't forget to invite Taiwan to the party