Prostitution is not simply legal, it's regulated. Brothels must conform to various legal standards, and are subject to government inspection. Various state governments have recognised that if we are to be serious about fighting AIDS, we need to ensure that prostitutes (working in and outside brothels) are safe, and will not spread any sort of diseases. I think it's a very clever thing to do. If thousands of years of modern human history has taught us anything, it's that prostitution always has existed, and most likely always will exist.
I would think this makes sense to most people.
To Australians, ensuring that AIDS doesn't spread out of control is far more important than any moral stand against prostitution.
Fighting for the glory of the Australian Republic.