Earlier quoted context omitted.
I know this is what the up-vote button is for. But I do want to add a redundant comment appreciating this explanation. It explains this adequately in three short paragraphs. The second paragraph is worth expanding from a little. As it can be argued that fear of anti-antisemitism among the left is well warranted. A good example of that is Jeremy Corbin constantly being accused of anti-antisemitism for criticizing the…
>Jeremy Corbin constantly being accused of anti-antisemitism for criticizing the state of Israel A 2 minute web search: https://www.theguardian.com/news/2019/may/01/jeremy-corbyn-r... "Before becoming Labour leader he called 1902 book containing antisemitic tropes ‘brilliant’. Jewish leaders have written to Jeremy Corbyn to express “grave concern” and demand an explanation after it emerged he wrote a glowing foreword…
My short web search found a secondary source[1] which debunks some of the claims you have mentioned here by offering a little more context around them. The Wikipedia page about Jeremy Corbyn has a whole section devoted to this[2] and all the claims are either vague or unsubstantiated.
Now I don’t personally know whether Jeremy Corbyn is an anti-Semite (he might very well be), but there is nothing which he has done which indicates for any amount of certainty that he is. The campaign to smear him as one has most certainly succeeded, and his support for Palestine probably in no small is to blame for this.
1: https://www.spectator.co.uk/article/is-jeremy-corbyn-really-...
2: https://en.wikipedia.org/wiki/Jeremy_Corbyn#Allegations_of_a...