The electorate by electorate results are really interesting, and give a great insight into the dimensionality of Australia's political divides. A lot of the 'no' areas are really strong Labor areas, and a lot of the 'yes' areas are really strong Liberal Party (i.e. conservative) areas.
But the 'no' vote takes two forms. One is high migration areas, like Blaxland, which I believe has the highest Muslim population in Australia (about 30% of the electorate). These areas are heavy Labor areas which are not at risk of swinging to the Liberal Party. The other is white working class voters, who have also traditionally been Labor voters, but who are much more amenable to voting for the Liberal Party. My electorate, for instance, is a 'no' electorate, and also a reasonably marginal Liberal electorate. But it's a traditionally working class electorate which was safely in Labor's hands before 2010.
So there's a strong contrast between the cosmopolitan, inner-city type constituency that someone like Tanya Plibersek is representing, and the constituency that her colleague Chris Bowen is representing.
Similarly in the Liberal party, there's a divide between the social and economic conservatives. Malcolm Turnbull supports marriage equality, and Tony Abbott does not. But they both represent North Sydney blue ribbon electorates which voted overwhelmingly 'yes'. Malcolm Turnbull is very much a good fit for his electorate in this regard, but Tony Abbott is not. He has been primarily appealing to the Western Sydney working class social conservative type, in a kinda Trumpian way, but those aren't the people making up his electorate.
Well, what is the alternative you were wishing for, exactly?
That conservatives were magically not homophobes even though you knew they were?
Or that they tactically - anticipating defeat - hide their homophobia and channel it bit by bit in all sorts of other... activity?
Yes, it would probably be too much to expect homophobes to not be, but firstly, that does not make their homophobia any less indefensible, and secondly, that's not so much the issue. There were enough parliamentarians to amend the
Marriage Act, and the postal survey was simply a device by the Turnbull government to deal with their own internal problems. Turnbull is under pressure from the conservative wing of the party, given his poor performance in the polls, and so believed that he could not afford to allow a free vote on the issue. So to preserve his own personal position within the party, he caved to the demands of the conservatives to put it to a public vote (these demands being made as a last ditch defence hoping for the emergence of some sort of silent majority). The parliament rejected an official plebiscite, because it's a waste of money and a pretty offensive concept. So Turnbull forged ahead with the voluntary, non-binding postal survey. This avoided the need for legislation, as it could rely on some pretty dubious executive action, which although determined to be legal by the High Court, was a clear stretch to dip into 'emergency funds'. A lot of the conservatives demanding the vote promptly announced, of course, that they would ignore a 'yes' vote in any case.