US is exempted for many requirement on FIRB as per ANZUS treaty, for example, an American buying properties is most likely to be exempted and most case were not even considered in FIRB.
China have about 30,000 case of FIRB application in 2016 on the other hand, only some 400 cases was considered in FIRB that was US origin. US application are mostly defence related issue, or high value investment, while for a Chinese citizen, they will have to lodge a FIRB application if they want to buy a house over 1 millions.
Yes, US held the second largest land ownership in Australia. I believe it was a company called "Cargill" which own approximately 18% of agricultural land in Australia.
It's nothing about Invasion, it's about the quantity of investment.
China is not the biggest investor of Australia, it was the US, by year, China may be catching up, but you did not factor in the fact that US have been investing in Australia since 1930s. China only started at the end of 1990s, you can look at the US investment vs Chinese Investment is (US) 26% to (China) 3% as of 2016
http://treasury.gov.au/~/media/Treasury/Publications and Media/Publications/2016/Foreign investment into Australia/Downloads/PDF/TWP_201601_Foreign_Investment.ashx
http://dfat.gov.au/trade/topics/investment/Pages/which-countries-invest-in-australia.aspx
Chinese pies is good, but still not at good as the US and EU, plus, according to FIRB, Chinese investment are mostly in residential properties, which does not generate much direct contribution, more than half of 46 billions investment by China in 2015 is from residential estate (26 billions or 53%) and since the FIRB reform, the residential market will soon be close off to Chinese, which mean the number of total investment from China is not going to be big.
https://cdn.tspace.gov.au/uploads/sites/79/2016/03/FIRB-AR-2014-15.pdf
In short, it will take a long time for China to dislodge US as the primary investor in Australia, if at all, and that, plus the defence ties is the reason why this cannot dislodge a US and Aus relation. The only way you can break this is for China to actually invade Australia and occupied it. Otherwise Australia is and always will be sided with US, not China.
Hugh White is a conflicted dude, I think he is living in La-La Land instead of reality.