When anti-semitism still appeared to be the Labour membership’s most glaring problem with intra-party prejudice and related mudslinging, great importance attached to definitions. What might seem to some members a perfectly allowable comment on the Israeli state might to others, using the International Holocaust Remembrance Alliance (IHRA) definition of antisemitism, be manifestly hateful and targeted.

The party’s adoption of that definition was itself disputed. Labour took on the IHRA definition in 2016, then argued about adopting its examples of antisemitic behaviour. As ugly as this difficulty with internationally agreed terminology might look from outside, the interest in precise wording represented some common ground. On the definition of antisemitism, Labour’s factions were at least able to communicate.

More recently, the party has adopted a working definition of Islamophobia advanced by the all-party parliamentary group on British Muslims (after consultation with more than 750 British Muslim organisations, 80 academics and 50 MPs). The group’s co-chair Wes Streeting dismissed objections that free speech would suffer. “While our definition cannot prevent false-flag accusations of Islamophobia to shut down reasonable debate and discussion, it does not enable such accusations. In fact, it makes it easier to deal with such behaviour,” he said. “Our definition provides a framework for helping organisations to assess, understand and tackle real hatred, prejudice and discrimination.”

Can it be damagingly transphobic for people to meet and discuss the possible implications for women-only spaces?

There could hardly be a better case for another considered definition – after a week in which its meaning has been both stretched and contested – of what should be understood by transphobia. Unless we want to leave that job to the courts. Is it allowed, for instance, to satirise self-ID, as in the case of Harry Miller? Yes, says Mr Justice Knowles. And in a passage that might have been inspired by Labour’s pledges: “Some… are readily willing to label those with different viewpoints as ‘transphobic’ or as displaying ‘hatred’ when they are not.”

There are obvious implications for the unprecedented debates prompted by a proposed reform to the Gender Recognition Act, facilitating gender self-identification (ID). Can it be damagingly transphobic – if Miller is not – for people to meet and discuss the possible implications for women-only spaces and safeguarding? Should people be able to meet, without fear of abusive crowds, to share concerns about early gender dysphoria diagnosis/affirmation? Is it actionably bigoted – unlike Miller – to question the fairness of male-bodied athletes competing in women’s elite sport?

The clear implication by prominent Labour leadership contenders is that all such debates are transphobic, even when the subject under discussion is, very often, female anxiety about the supremely non-trans threat posed – or not – by a minority of men. The principal threat to the safety of women, trans and not, is arguably identical. Somehow, as the Fawcett Society’s Sam Smethers said, we need to “move this agenda forward”. But Rebecca Long-Bailey seemed to find more common ground with the activists outside against gender critical meetings. “We need to end the discussion [on self-ID],” she told Newsnight.

The identification of transphobic behaviour requires no laboriously agreed or court-won description

As with antisemitism, the identification of transphobic behaviour, at its insulting or threatening worst, requires no laboriously agreed or court-won description. For further clarity, the Crown Prosecution Service offers guidance on the kind of behaviour that might make an incident or crime transphobic. Such as: “Was there any use of derogatory language that referred to sexual orientation or transgender identity?”

The Labour Campaign for Trans Rights was plainly referring to a different order of offences in the statement and pledges now endorsed by Lisa Nandy, Emily Thornberry, Dawn Butler, Angela Rayner and Long-Bailey. “There are still transphobes in our ranks,” it states, “and we have often failed to act as transphobia has gained ground within our party.” Transphobic views and policies are cited, without examples, along with allegedly transphobic activists, who are, however, identified.

Pledgers demand a “fight against transphobic organisations such as Woman’s Place UK, LGB Alliance and other trans-exclusionist hate groups”. Both groups have supporters – possibly news to people who may not previously have been gripped by the gender-critical debate – who are themselves trans, as well as many well-known and veteran campaigners for gay rights.

Facebook Twitter Pinterest Lisa Nandy has observed that organisations are ‘wilfully ... causing offence’ in the trans debate. Photograph: Jacob King/PA

A legal response by a maligned group could yet yield, again in court, some embryonic definition of transphobia that, as with antisemitism and Islamophobia, could at least provoke dialogue, rather than shutting it down, and more Twitter wars. Given the lack of either examples or argument to justify the threat of mass expulsions, last week’s Labour pledges read – phobia-hunting aside – as disturbingly undemocratic. Without dialogue, opposed groups can only polarise further, with one result being, as Scott Aikin and Robert Talisse argue in their forthcoming book, Political Argument in a Polarized Age, that people become unwilling to regard their opponents as political equals. “Bye”, as unconcerned purists last week taunted the thousands tweeting #expelme in response to Labour’s pledges.

Leadership pledgers appeared similarly uncompromising on what level of disagreement, if they won, might be allowed. Nandy, observing that the debate “has descended into pitting people against each other”, offered, by way of improving it, that one organisation has been “wilfully trying to go after trans people” – evidence pending – also, “causing offence”.

In a Nandy-led world, then, the Islamophobia definition might need some more work. Its authors made clear, as does the Miller case, that human rights do not include the right not to be offended or to have your spiritual, or other non-negotiable private convictions, affirmed by fellow citizens. Perhaps a large body of opinion does expect public figures, such as Nandy and Long-Bailey, to denounce public conversation about self-ID and women’s sex-based rights, to prohibit mention of biology, and condemn as a “hate group” – categorised, then, with far-right terrorists – any disobedient voices. But the case for such unique protection must surely begin with something more reasoned – and democratic – than the 12 pledges.

• Catherine Bennett is an Observer columnist