There are people of other religions who also recognise the importance of morality. If Australia is a representative democracy this requires that the voice of such persons be heeded. They have a right to a decisive voice in public affairs. It is falsely argued that moral values are outdated. This is false.
Christian values embody eternal truths which have attempted to follow over the years.
Moral values have been followed by other civilisations. Roman civilisation at the height of its fame and prosperity recognised the importance of basic moral values. The decline and fall of the Roman Empire is associated by historians with the spread of immorality and the over-reaching power of government. This is an oversimplification and misrepresentation. The answer is not that biblical principles will lead to Utopia, but that they offer a firmer basis for dealing with the problems of life than the values which have underpinned modern age law and social reform.