From Keith's link:

There's a certain section of his supporters, not all of them, that really struggle to understand that you can be a Jew and in the party and also support Israel without being a supporter of the right wing," said Hannah, who asked that her name not be used for fear for her safety. "It's black and white to them. If you have any sympathy for Israel, they are triggered and can't control themselves."

Hannah said that since Corbyn became the Labour Party's leader in 2015, she has received "countless" anti-Semitic messages on social media, including a particularly distressing photo of a man with a knife in his back and the caption, "Serves him right, he trusted a k---," using racial slur for someone of Jewish descent.