I wrote a backgrounder on the ACCC vs Google and Facebook stoush last year, if you're just catching up now: https://www.eigenmagic.com/2020/09/07/a-deep-dive-into-google-facebook-and-australian-news/
Some quotes and links to follow.

According to the ACCC, there is a “fundamental bargaining power imbalance between Australian news media businesses and major digital platforms” but I’ve yet to see an explanation for why this power imbalance is fundamental.

Apparently all the existing competition laws have proved no match for the ingenuity and cunning of these digital platforms, despite the ACCC’s best efforts to address this budding market failure before it got this bad. Like this one: https://www.thelawyermag.com/au/news/general/accc-permits-proposed-media-merger-with-jws-help/220692

If we’re going to talk about a market failure, we need to be clear on what market we’re actually talking about. Are we talking about the market for news, or the market for advertising?

For a number of years, the news orgs have tried to negotiate with Google and Facebook and failed to get what they want because they have a terrible bargaining position.
Capitalism is great when you're winning, but sucks when you're losing, I guess.

The ACCC asserts that “a strong and independent media landscape is essential to a well-functioning democracy” but doesn’t bother to explain why.

It’s simply assumed that this idyllic state of affairs will magically spring into existence if additional money flows from Google and Facebook to this fairly small (and specific) subset of Australian media businesses.

It seems especially odd that something this vital to a well-functioning democracy requires two specific multi-nationals to directly subsidise their vanquished marketplace competitors, while ignoring the multitude of alternatives that have sprung up to replace them.

People don’t so much want the media to win as to see Google and Facebook taken down a notch as payback for all the things they’ve done wrong.
This is a performative morality tale, not a nuanced discussion of public policy.

It feels like Google has mistaken people using its products for liking Google.
Most people have bank accounts but we all hate banks.

The fact that people use Facebook doesn’t mean they like the company. They use it because they feel that if they don’t, they’ll be cut off from friends and family who spend so much time posting racist memes in there.

As many others have suggested, if there is a market failure, the intervention should correct that failure for the entire market not just a subset of the players who happen to have the ear of a friendly regulator.