It's not surprising given the LNP was refused a conscience vote. Although even then I imagine less than 1/3 of the Liberal MPs would have voted for freedom from Statist interference and the right of individuals to form contract by mutual consent.

Yes, I am doing that deliberately :)

Alex Greenwich did try hard to promote the issue as "marriage equality", but a lot of the media and detractors called it "gay marriage". I rather suspect however, that didn't make too much of a difference to the overall vote. Those who are bigoted against gay people are not swayed by the equality argument.