The short (and exceptionally tongue-in-cheek) version? Far-left Communists are anti-capitalist, they see Jews around the world as supporting Capitalism, cite conspiracy theories that they "own all the banks and money", and a number of people possessing these views and conpiracies have infiltrated the party and under Corbyn's Labour, they became more emboldened in voicing them online.
It turns out that a number of Labour Party members/advocates still believe in old, outdated and antisemitic conspiracy tropes about "the Jews running the world" or "the Jews are responsible for every social tragedy" or "the Jews are the cause of all wars". Yes, these are actual conspiracies that go back hundreds of years, so it's not a recent thing, namely the one I underlined. "The Jews are secretly orchestrating a race war to stay rich!" You know, that sort of ignorance.
Peake's idiotic attempt to connect George Floyd's murder to 'Israel Secret Service' tactics, indicating that Israel was in some way responsible and therefore is a reprehensible community, is a prime example of this tone deaf attitude that has surfaced about "Jews being responsible for every national social tragedy in history". RLB supporting the article, and thus the comments and then failing to apologise after being called out on it, is an example of an attitude that has plagued recent Labour MP's.
There's a long standing narrative within the more extremist, far-left, anti-capitalist elements that Jewish banks, businesses and employers are continuing supporting capitalist regimes across the world, so they are considered by some as "the enemy within". In the last few years this element has become more vocal and a lot of sources keep pointing back to Labour members, be they fringe or connected to the party itself. The defence is always "we're not critical of Jews, we're critical of Israeli govt!" as a cop out, but the fact is that Peake mentioning the 'Israeli Secret Services' was not a critique of the Israeli govt. It was an example of a belief in a conspiracy theory that Israel has helped train the US in a tactic solely designed to incite a racial divide in the US.
Bang on.
Look at the mural Corbyn openly supported.
It’s straight out of the Joseph Goebbels school of propaganda.