Actually, there is. There's 2 bodies that do censorship in Australia.

OFLC reviews media for compliance. It's an independent body that reports to Parliament.

ACMA is responsible for online/broadcast regulation. It answers to the Minister for Communications (ie Conroy). It refers things that it thinks need to be classified to the OFLC.

Actually, you're not required to vote. You're required to attend a voting place or submit an absentee ballot and get crossed off the electoral roll.

What you decide to record on your vote (including nothing at all) is up to you.