Jeremy Corbyn is under fire, again. Guido Fawkes revealed that the Labour leader spent Passover at an event hosted by a far-left group “Jewdas” that has called for the destruction of Israel, dismissed the Labour antisemitism scandal as “right wing manipulation” and labelled Corbyn’s Jewish critics “non-Jews”.

Corbyn’s most ardent supporters, including Guardian commentator Owen Jones, are defending their hero by pointing out that Jews do not have a collective “world view”. Left wing Jews, anti-capitalist Jews, fervent critics of Israel, and even Jews who dislike other Jews are all equally “legitimate” Jews, and the members of Jewdas should be able to share their opinions without gentiles suggesting otherwise.

Of course, in as far as the argument goes, these supporters are right. Lots of “mainstream Jews”– though they disagree with Jewdas on a number of issues – believe that the group has its place in the Jewish community. There is a richness to the political plurality of modern Judaism, and it should be celebrated.

The problem here is that Jeremy Corbyn is not celebrating plurality. If he were truly trying to repair the badly damaged relationship between the Jewish community and his wing of the Labour party, he would have spent the last few weeks going to all kinds of Jewish events, speaking to Jews across the entire political spectrum and listening, with humility, to what they all have to say.

That is not what he’s been doing. In fact, it seems he’s only been to one Jewish event since he became mired in a huge antisemitism scandal, and it happens to have been run by the only faction of the Jewish community that has placed itself very firmly on the “this is a witch hunt” side of the debate. Jewdas’s official line on the antisemitism row is that it’s “the work of cynical manipulations by people whose express loyalty is to the Conservative Party and the right wing of the Labour Party” – and a “ right wing smear” on Jeremy Corbyn.

So what was Jeremy Corbyn thinking when he went along to this particular Seder celebration? Well, there are two explanations.

The first, and according to many the most plausible, is that Jeremy Corbyn was being deliberately provocative. In spite of his promises to “eradicate the cancer of antisemitism”, his black and white world view (in which Zionists are Public Enemy Number 1) makes him stubbornly blind to the antisemitic behaviour of his far left tribe. When moderate Labour MPs like Wes Streeting point it out – as he did so eloquently as last week’s rally held outside Parliament – Corbyn  cannot take it seriously, and genuinely interprets it as a smear against him.

He can’t say this, because even he realises that the Leader of the Opposition speaking out against antisemitism protesters in his own party would result in a massive backlash, so instead he does the next best thing: he goes and has dinner with those who have spoken out against it, showing, through actions if not words, where he stands.

The other explanation – which seems to be surfacing a lot at the moment – is that Jeremy Corbyn is naïve, tin-eared, and rather stupid. He had a free evening, and, temporarily forgetting that he is the Leader of the Opposition and is at the centre of a massive scandal about antisemitism, went along to spend a relaxed evening with some young people near his home in Islington. In the same way that he only “glanced” at the antisemitic mural before commenting on it on Facebook in 2012, he only vaguely registered what Jewdas’s views on Leftist antisemitism are before going along to their Seder. According to this reading, he is on the verge of meeting a load of other more mainstream Jewish groups, and didn’t see the harm in starting with Jewdas.

The truth probably lies somewhere in between. Corbyn half wanted to make a political statement, and, because he is a vain man who quite fancied the idea of spending the evening with some adoring young fans, didn’t think for long enough about exactly what that statement should look like.

Politically, one of the most interesting aspects of this whole shocking-but-predictable affair is that for the first time, the cracks are showing in the Corbynista movement. The messy reality of having Jeremy Corbyn as a leader seems to be dawning on the far left pressure group Momentum, finally. Jon Lansman – founder of the group – is at pains to point out that Corbyn’s office knew nothing of the evening, implying that dear old “magic grandpa” just pottered off on his own without consulting anyone. He has gone as far as to say that the Leader of the Opposition should go on a training course to increase his awareness of antisemitism.

The brains behind Corbyn – Lansman and McDonnell – have both, in recent weeks, publicly distanced themselves from him. McDonnell broke with Corbyn on Russia. Although the three see eye-to-eye on how they want Britain to be run, McDonnell and Lansman seem to be getting frustrated with the flip side of their leader’s supposed “authenticity”. Corbyn exhibits tin-eared and clumsy political naivety, mixed in with dangerous obstinacy.

Perhaps, the Labour leader once termed an “absolute boy”, isn’t the Messiah after all. What was it Monty Python said again?