I would peg Australia more as an authoritarian liberal country rather than conservative. Most states in the US are far more conservative than Australia.

Australia IMHO has never broken out of the colonial mindset, where the government knows what is best for you. Beyond drugs, that includes pervasive censorship of movies, books, video games, Internet etc. The lack of First and Fourth amendment style protections means that ultimately the government has the final call on these topics, and for whatever reason, neither of the two primary political parties seem inclined to change the status quo.

The hypocrisy of it is quite transparent. Last I checked, possession of cannabis and X rated pornography is illegal in all states and territories of Australia, except for the Australian Capital Territory which is the equivalent of DC. Which of course is where most of the politicians are.