Labour has suspended Ian McKenzie, chair of its Lewisham East branch, over tweets he sent in 2015 and 2016.

Responding to comments by Thornberry (who was shadow defence secretary at the time of his tweet about her) opposing David Cameron’s decision to bomb the terrorist group Islamic State, McKenzie mocked the idea of negotiating with them.

“Maybe she’d agree sex slavery to one man only, provided he didn’t sell her on or insist on gang rape,” he tweeted, in December 2015, as part of a thread asking how one would bargain with IS.

He returned to the subject in January 2016: “Emily Thornberry is too old for ISIS. They won’t make a sex slave of her. They’ll behead her and dump her in a mass grave.”

What’s wrong with these tweets?

First, they are misogynistic. They undermine a woman’s political argument not with a counter-argument but with imagery of sexual violence being inflicted on her by bloodthirsty men – and then having a pop at her age, to boot.

Second, they are disloyal. Thornberry is a Labour shadow cabinet member – a far higher level of seniority than McKenzie, who chairs a constituency branch. Party activists can disagree with their leaders – and very often do – but they can’t get away with making rape jokes about them (and nor should they about anyone else, for that matter).

On the flipside, as a local party leader, McKenzie has a position of power himself. What example is he setting with these tweets? He’s suggesting that this kind of language has a place in modern British politics, and is also suggesting to other activists that rape jokes about women are OK.

Well, they’re not. Something that the multiple centre-left commentators (The Times’ Phillip Collins and Telegraph’s Dan Hodges, for example) and fellow Labour politicians (like Baroness Ann Taylor and Ilford South MP Mike Gapes) defending McKenzie know full well, if only tribalism weren’t blinding them in this instance.

And no, “but what about John McDonnell’s comment about lynching Esther McVey?” doesn’t count as an argument. Not unless what you’re trying to reveal about yourself is that you only condemn violent misogynistic imagery when it suits your politics. In that case, it’s very convincing.