This argument is ridiculous. No one has forgotten that ebay is a commercially run business. You seem to be forgetting that they have a monopoly in online auctions. It is illegal for a company to use a monoploy in one market to gain a monopoly in another market. Ask Microsoft how their decision to use their OS monopoly to try and get a monopoly in browsers panned out. What ebay has done is even worse though, because they are purchasing companies and then trying to control the new markets through their monopoly. If you think that companies should be able to build monopolies and then buy more monopolies, then you will be living in a world with very few choices.
Now you seem to be forgetting that ebay is a commercial operation, whereas the Australian Government is governmental. That is a huge difference.
That is easy enough to say, if you never want to sell anything of significant value on an online auction ever again (except maybe domains). Ebay has a monoploy on online auctions, and so since there are no other viable alternatives, they have to play by a different set of rules. That is just the way the law is. They will only be able to tip toe around it for so long.