In the week leading up to the tightly contested Batman by-election in Melbourne’s inner north, a social media storm erupted in what has become colloquially known as #placardgate.

The offending placard, carried at a Refugee Action Collective rally in the Batman electorate on 10 March, was a defaced corflute that had been promoting Labor’s candidate, Ged Kearney.

Her face was circled with a texta and crossed out, and the refugee campaign demand to “close the camps now” was scrawled below.

The placard was a sharp, entirely political, if provocative, critique of Ged Kearney’s candidacy by the left wing activist group Close the Camps Action Collective (CtCAC). It highlighted her refusal to break publicly with the ALP’s anti-refugee policies.

Other placards carried by CtCAC at the rally labelled Liberal and Labor refugee policies as “the same,” while pointing out that these policies “kill refugees” – all statements of fact that make many Labor members ashamed of their party.

When she was Australian Council of Trade Union president, Kearney had a strong track record of arguing for the trade union movement to oppose offshore detention, boat turn-backs and deportations to danger. She also spoke at numerous refugee rights campaign forums and demonstrations.

But after her candidacy was announced, Kearney was quoted in a Herald Sun interview saying that Labor’s anti-refugee policies were “a reality I accept” and that she would “respect” the decision of the 2015 ALP conference, which enshrined boat turn-backs as party policy.

The “reality” that Kearney accepted was the well-trodden path of all progressives-cum-ALP parliamentarians, which is that to get ahead in the party, you have to leave your integrity at the door.

Instead, she will publicly toe the line and “respect” caucus discipline – which means adding her vote in parliament to consigning people fleeing persecution and war to concentration camps on Pacific Islands. Whatever arguments she may conduct behind closed doors, her vote will be to turn back the boats.

Since the Herald Sun interview, Kearney has determinedly attempted to bury the question of refugees. Meanwhile, Greens candidate Alex Bhathal has put the demand to “bring them here” at the forefront of her election campaign and has a strong history of refugee advocacy.

At the Batman refugee rally, Bhathal was the only candidate prepared to speak from the platform. Kearney had been invited to speak, on the proviso she spoke to support the rally demands to end offshore detention, but unsurprisingly declined to attend.

Kearney would not have been isolated if she had spoken out publicly against Labor policy. It would have been overwhelmingly popular in the electorate and it would have amplified the call by members of the NSW Labor left for the ALP to dump support for offshore detention at the ALP national conference scheduled for July. If there were a time to speak-out to advance the argument in the party, it is now.

Kearney was in a strong position to stick her head out – her candidacy is a last ditch effort by the ALP, after the right wing disaster that was David Feeney, to stop Batman from turning Green. But party unity, lining up behind Bill Shorten’s leadership, was deemed more important.

In the aftermath of the Batman refugee rally, there were howls of outrage from union movement leaders. These were not directed at Kearney for backtracking on previous commitments. They were aimed at the Greens and Alex Bhathal for what amounts to being photographed, unknowingly, near an anti-Ged placard that pointed out the sad truth.

This placard, we should remember, was neither made by the Greens, nor was it held by a Greens member, let alone by Bhathal. Video footage shot by Anthony Snowden, an independent chronicler of protests in Melbourne, later confirmed that Bhathal even asked the activist holding the placard to move to another part of the march so she wasn’t seen to be endorsing the placard.

But let’s not let facts get in the way of a good story. And so the social media pile on began.

Luke Hilakari, Victorian Trades Hall secretary, decried the “disrespect” shown by the Greens to “our” national president, forgetting that Kearney had resigned from the role of national president to contest the election. Never mind that, as ACTU president, she oversaw the continued decline in union membership, strike levels and the stagnation of workers’ wages.

Columnist Van Badham, who is rumoured to be an ALP candidate in a northern seat in the next state election, weighed in with some truly mad online trolling. She labelled the placard sexist because, you know, it politically criticised a woman. She even absurdly likened the placard to the openly misogynistic “ditch the witch” LNP mobilisation during Julia Gillard’s reign, and demanded an apology from the Greens.

Interventions came flooding in from as far afield as Canberra, with Alexander White, former Labor student politician turned Unions ACT head, adding his two cents to the attack. John Setka, CFMEU Victorian state secretary, disingenuously tweeted: “Sad state of affairs when Greens use Labour Day weekend to campaign for another term of Turnbull/Liberal government”.

This confected outrage was not driven by genuine concern about how to build the strongest refugee rights movement. As Jeff Sparrow, left wing political commentator tweeted, “If you’re more outraged about a poster criticising mandatory detention than you are about mandatory detention then something is very wrong”.

No, the twitter angst was primarily designed as a tool of distraction. It aimed to shift the narrative away from Labor’s appalling record on refugees.

It also sought to feed the apolitical character assassination, circulated by Bhathal’s rivals within the Green’s and by the Labor Party, labelling Bhathal a bully.

It should be beneath the union movement to participate in this tawdry smear campaign. But sadly, many of today’s union leaders have forgotten that our movement should have an independent existence. Our unions should not primarily be vehicles to improve Labor’s electoral fortunes; they exist to improve and struggle for workers’ rights.

Victorian unions should not be using union resources to back the ALP campaign against the Greens. The Greens are not only better on refugees and Adani; they have a more pro-worker industrial policy.