the people who dont believe in it seem to think that disinterested in politics equals bad decision-making, and that only interested persons voting is somehow more valid. this seems to be founded on a basic belief that interested somehow equals informed and/or intelligent.
look at the usa and you will see that none of this is true. do we REALLY want things to be like that?? the people who vote in the usa are not more intelligent, more compassionate, more benificent, or more informed. very often they are extremists, and the strength of certain factions (such as the christian right) makes the representation unbalanced in certain directions, which do not accurately represent the wishes of the american people.
removal of compulsory voting allows the more powerful (and, generally, wealthy) groups in society to have a greater say, whilst the disillusioned less powerful just give up and stop voting all together, cuz they dont see the point. got a bit of orwellian dilemma of the proles to it, imo.
who on earth wants to be more like the usa?!? i mean REALLY.... compulsory voting also helps to protect against absolute corruption (as in the usa), the cycle of disillusionment leads to disinterest leads to nonvoting leads to dodgy corrupt politions leads to more disillusionment.. and so on. we have some element of that in australia, but i think compulsory voting slows that process down quite a bit - our pollies are nowhere near as corrupt or morally bankrupt as in the usa (although we're working on it apparently...)
in theory at least (and nothing in practice works like the theory) compulsory voting imposes a certain degree of civic responsibility that helps to mitigate the overwhelming laziness, disinterest, and disillusionment of most people. sure people are still like that, and many of them donkey vote or vote for parties who will not really represent their true wishes - but at least they have a say.
and sure, this time around a lot of disinterested or uneducated or stupid people voted against their own best interests, but that was their decision to make, however lazy and uninformed it might have been. it was still their choice. to begrudge them a voice leads us to quite dangerous waters.
one person, one vote. its really the only way to maintain even a semblance of democracy or balanced representation. however flawed it might be, its still the best system we've come up with yet (along with some fine european countries). until we come up with something better, i think we should stick with it.
i also believe people (as a group) get the government they deserve, if you are lazy and avoid your civic responsibility to think about the issues, well you cant really complain when you're unhappy with the consequences can you? especially in au where everyone votes.