In the previous decades, it was common practice for Asian companies (especially Japanese) to have cross ownership share holdings in each other. That way they can influence prices, policies, etc of their counterparts, often to the detriment of the small shareholder. The Chinese being relatively new to the game believe they can do this. However, they do not understand that it is not possible in Australia because BHP (and other companies)have to consider the interests of ALL shareholders, not just the major ones. Most of the time, we'd like to think that there are clever brains behind big money - lately, we have witnessed these clever people are subject to the same horrendous mistakes as the average punter.

At the same time, China has about $1 trillion in reserves, most of which is in US$. $20 Billion is a drop in the ocean but if they can buy that much of BHP, that money is at least not tied to the US$.

Good points though

They are seeking to take ownership of the companies which are costing them so much, for several reasons.
1) to recover some cost (profit, generated from itself. Zero sum situation).
2) to aquire controlling amounts of the company stock in order to hamstring the aggressive negotiations.

Current investors of BHP should be very against chinese ownership, as they will purposely generate lower profits because they'll start discounting their own product indirectly via special deals and not increasing the contract amount as much as they could.

Australian public should also be very against chinese ownership, as pretty much every single tax cut we've gained in the last 20 years has come on the back of strong profits from BHP and RIO.

The good news is that both sides of Australian politics understand this, and any move by Chinese soverign funds to take significant ownership of these companies (or any other outsider) will be blocked in the national interest.