On the contrary, I have a very high opinion of the institution of marriage. The problem is the lack of respect for long established institutions, of which marriage is one.
As I said, I have no problem with the SS getting all the legal benefits of marriage, but don't call the union a marriage because it never will be a marriage.
Prior to the Howard government amendment to the Marriage Act in 2004, marriage was defined in common law. Howard did not like that courts could decide that marriage was, so inserted a definition into the Act that stated 'marriage means the union of a man and a woman to the exclusion of all others, voluntarily entered into for life'. The result of this is that Parliament now decides the definition of marriage, not the courts. So, if the definition of marriage is changed in the Marriage Act to include same sex couples, then such a union will certainly be a marriage, regardless of what you and I think about it.