That phrase has come to signify and encapsulate the issue: Jews perceive Corbyn as a threat.
There are 2 scenarios/explanations:
1. Corbyn & his team have decided to directly threaten British Jews.
It could be either.
In the first scenario, they will be able to plausibly deny a direct threat. It's impossible to prove that they meant it as a threat.
a) The Jewish fears of the threat that Corbyn represents have made so little impact on them that they absolutely didn't even think of the risk of using this very particular language.
d) It could be a mixture of all 3, with different members of the team coming from each of those positions
Naturally, the history of the Jews is used as proof.
And still it persists on the Left today.
So - anyone with even an iota of care might think:
It's not hard, is it?