There are number of other aspects and examples of this phenomenon it would be worth mentioning, in connection with Momentum.
For instance, when Fidel Castro died, Momentum put out a statement which read as a fairly uncritical paean to his regime. So we suddenly discovered that an organisation whose leaders think or pretend to think it would be wrong to have policy on broad areas of Labour Party policy, has a policy on the Cuban government! A policy decided purely by the Momentum office naturally. This was before the 10 January coup, but there was as usual no attempt to consult the elected NC or even the Steering Committee.
I challenged a few central Momentum office people about this, and the responses I got were very instructive. One in particular, which was: I'm not a big fan of Castro myself, but don't know you know this is what the movement thinks, and any way we can't say anything out of step with what Jeremy will be saying. And read the statement carefully, it has hints of a more critical view (sort of true, if you were looking for them very, very hard indeed).
So we see in action the ludicrousness, incoherence and hypocrisy of the idea that Momentum shouldn't or doesn't have policy; the unwillingness to - not even criticise Corbyn - but say anything distinct from him; the falling in with dominant labour movement left "common sense"; but also how in practice this leads to Stalinist or Stalinist-ish positions.
(I wondered if the people clustered around the Momentum office on some level, maybe not fully conscious, admire Cuba's undemocratic but supposedly "progressive" regime, but other comrades told me that was an argument too far...)
A student comrade reports how at recent NCAFC conference, a small group of "Lansmanite" youth turned up to move a motion arguing that the left should support withdrawal from the EU, that defending free movement from the EU countries somehow cuts against arguing for migrants' rights more generally, and that only after the EU has been broken up can a socialist Europe emerge. (They were heavily defeated.) In other words: a Stalinist or at least Stalinist-influenced position.
Meanwhile, although out and out Stalinists are relatively small minority among young supporters of the Momentum "leadership", they are treated with friendly acceptance by the majority, and their repulsive references to Stalinist witch-hunting and slaughter of Trotskyists in the 1930s - "Correct position", "Vigilance", "Clear them out" and so on - have become common usage in these circles. I suspect that as things develop many of young careerists are adopting elements of their politics, no doubt in softened form, too. Are we seeing a renewal of official labour movement Stalinism for a new generation?
All this is not without contradictions: for instance, many of those working or volunteering at the Momentum office are apparently unhappy about the Labour leadership's retreat on free movement and migrants' rights. We should not fall into scatter-gun or indiscriminate use of terms like Stalinist. But to deny the influence of Stalinism in Momentum is to ignore the facts, and we need to challenge the better people around the leadership about this.