The protest is in the visible lack of turnout, and more relevantly in the lack of turnout of voting blocks that have historically shown up. Still agree?
I know that this is hard for you guys.
So I'll simplify it with an example scenario, which also tests your democratic moral logic.
Which is more democratic?
An election of Kim Jong Un in North Korea with 100% compulsory turnout. Or
An election of Kim Jong Un in North Korea with 5% non-compulsory turnout?
The answer, very obviously, is that the scenario with 5% non-compulsory turnout is more democratic.
This is the correct answer because the 95% that did not show up to vote would be seen by the world as a protest vote against a corrupt system. This is a necessary and valuable democratic mechanism. As it deprives Kim Jon Un's corrupt government of democratic legitimacy.
As it stands, North Korea has 100% voter turnout.
Do you want to veer toward or away from North Korea's model of "democracy"?
What you have in Australia is publicly visible compulsory turnout, period. Aside from whatever you might do privately in the election booth.
You can claim that Australia is a model of non-corruption. Maybe it is.
But compulsory turnout sure is a large step in corrupting elections, and one could argue a hallmark of corrupt elections. As well as a highly unusual shared characteristic with the most corrupt governments in the World.