What if most people support these laws? What happens when a democracy decides to vote away its own freedom? Should it be somehow prevented from doing so?
This is a classic example of the tyranny of the majority, and why government of any kind, democratic or not, is illegitimate. Any institution that wields power over you will eventually deprive you of your freedom against your will.
And without a government, i.e. without some entity with a monopoly on force, what happens then? Do I have to do battle on the streets every time I buy groceries or go to work?
I guess in the end, democracy or not, you get the government you deserve. Australians voted these guys in, they tolerate their actions, and many Australians will applaud them. If it all goes well, great. If not, I won't have much sympathy for them.
This is not an attitude I like to have, mind you, because I find that wherever I see tyranny in the world, I believe that to some degree - sometimes a lot, sometimes only a little - the victims of that oppression had it coming.
