For those who needed persuading that Malcolm Turnbull is trapped in an unhealthy, co-dependent relationship with his party's hard right, his approach to the proposed plebiscite on same-sex marriage clinches the matter. The problem isn't just that the Prime Minister affirmed Tony Abbott's manoeuvre to stymie marriage equality by way of a popular vote. On the contrary: for a while I even saw some merit in the plebiscite idea, although the Brexit poll, with its cautionary lesson about the inherent unpredictability of yes/no contests, rattled me enough to opine against it. But Turnbull's cowardice has further tainted the proposal with bad faith and it deserves to be voted down in the Senate.

Ideally, a popular vote might have exposed the sham arguments of the "no" same-sex marriage camp, their intoning "thousands of years of tradition" (as if, by some strange law of physics, time calcifies as weight), "freedom of religion" (that's the freedom to impose religion on others) and the one that takes the cake for disingenuousness and chutzpah, that by legislating for same-sex marriage the state expands its power over our lives (a stance that's only coherent if it advocates the complete abolition of marriage, but these conflicted libertarians won't go there.) Yes, a plebiscite would give a platform to hate – but also to love, in all its diversity.

A "yes" vote would confer political legitimacy, burying the idea this social reform is only beloved of an out-of-touch elite that's either too scared or too lofty to test their convictions in the court of public opinion.

So a free vote for marriage equality should have been celebrated as an opportunity – not supporting it looked like a tactical error on the part of Labor and the Greens. Yet all this was before Turnbull's persistent appeasement of the religious lobby undermined the integrity of the plebiscite concept.

The dead give-away is the provision of equal public funding for the "yes" and "no" campaigns – which reportedly arises from a promise Turnbull made to church leaders earlier this year. Even if many baulk at the prospect of their tax dollars financing odious attacks on same-sex families, the plan gives an illusion of fairness. "Any funding provided to the 'yes' or 'no' case will be scrupulously equal and fair," Turnbull told Parliament last week.

Let me ask, not entirely in jest, why the "no" campaign needs $7.5 million to prosecute its case when it can invoke thousands of years of traditional marriage as precedent, not to mention the last word in celebrity endorsements from The Almighty. Let me also ask, this time with complete sincerity and without malice, if funding both sides equally would exacerbate an existing inequity.

As others have pointed out, the churches already have a publicly subsidised pulpit for their views on traditional marriage, views they propagate both overtly and subtly. They reap generous tax exemptions for their operations, on top of "thousands of years" of wealth accumulation – a head start not even the cashed-up pink community can rival. They get government funding for chaplaincy programs and faith schools. In a post-religious society, religious institutions continue to enjoy a privileged status and uncontested legitimacy. As a matter of reality for funding to be "scrupulously equal" the non-institutional, Johnny-come-latelies in the "yes" camp ought to get more. The only practical answer is that neither side should get a cent.

Another sign that the plebiscite isn't what it purports to be is the government's silence on the consequences of a "yes" vote. In recent years the more intelligent opponents of same-sex marriage have changed tack from outright rejection of gay nuptials to arguing the proposed reform is legally and philosophically fraught, so much more complicated than the equal love simpletons can grasp. This line of attack centres on freedom of religion and conscientious objectors.

Sure, this crowd says, should the Marriage Act be changed, clergy won't be compelled to solemnise same-sex marriages, but what about the pious cake maker forced, under threat of anti-discrimination laws, to violate their beliefs by supplying goods to a gay wedding."You only have to look at the US, Britain, Canada, Ireland and elsewhere to see examples where individual conscience has been traduced by increasing state and judicial power," wrote federal MP Andrew Hastie in The Australian on Tuesday.

Let's assume Australia is indeed home to wedding planners so zealous they would put their conscience above their balance sheets, cake makers prepared to supply gay couples with a three-tiered Black Forest for a casual soiree but who will emphatically refuse the same transaction if the occasion is the couple's wedding. Allowing these traders to follow their conscience would mean allowing them to repudiate the laws of a secular state. It would amount to a declaration that married gays are not equal after all. Unless, of course, the opt-out laws would give similar latitude to the atheist cake maker who cannot countenance supplying the Black Forest to the heterosexual couple planning a church wedding.

Now the cake maker is an admittedly extreme example. But Turnbull has not explicitly rejected calls for freedom of conscience exemptions to be introduced should same-sex marriage come to pass. And the fact I can't rule out his succumbing to this kind of pressure, says volumes about his bona fides on marriage equality.

Julie Szego is a Fairfax Media columnist, author and freelance journalist.