Tbh, I don't think this is as much a victory as people like to believe.
Yes, SSM won the vote. However, it didn't hold a total majority - when you take into account how many people actually voted, only 49% are vocally for SSM. This holds true for several electorates, as well, including the infamous Menzies. A good argument, and hopefully the way many see it, is quite simply if the 20% that didn't vote cared enough to change the law, they would've voted. Unfortunately, this is still fuel many can use for the fire against us in the LGBTQIA+ community.
Not to sound defeatist or anything - this is a step forward past the step back that the whole vote was. But, there's still a long way to go, so hopefully people don't see this as a chance to let up. Even after the bill passes (because, let's be real, it's almost political suicide for most of the MPs to not vote for a SSM bill, unless it's as atrocious as the Patterson bill), there'll be hell to pay.