My PhD was in Holocaust studies; the people I've been most careful to listen to on this are the friends and former colleagues-many of whom are Jewish-whose business it is to study, interrogate and analyse antisemitism. This is what I've come to:
Jeremy Corbyn is not an antisemite.
There has been, and probably still is, antisemitism on the left, though often that's not properly distinguished from criticism of Israel (a nation state, a political entity, and therefore a just target fro criticism). And Labour have been too slow to react and were initially defensive, this was not good. But their opponents have made much hay with every single snippet, while ignoring the out-and-out racism of the other parties/candidates. I find it sad and telling that concern for antisemitism in the UK only appears when it can be used as a stick to beat a left-wing Labour leader.
Antisemitism is serious, on the rise, and historically disastrous, as well as being, in plain terms, morally wrong. It is endemic in British society for many reasons; one I think is massive ignorance about Jewishness and the other is historical bigotry that has gone unchallenged and is often invisible. I do not-for a minute-think that the Tories are any less antisemitic. Much like that of the Christian Right in America, there are some forms of support for Israel that are motivated to keep Jewish people in one place, with a single representative who can be bargained with. For this reason I also find the Chief Rabbi's comments (he is a friend of Johnson's), but moreover the reporting of them, deeply problematic. No-one is appointed to represent all British Jews and to suggest that is to attempt to corral them into a collective identity; its a form of stereotyping just as egregious as the calls, post 9/11, for 'muslims' to apologise.
The Conservative party will be worse for minorities-all minorities. Johnson has made his feelings about them crystal clear. I know people think voting Lib Dem is option C, but it is really just a vote for the Tory party. All Lib Dem seats can give us is a Tory majority. If you don't want that-and there are so many reasons not to-I urge you to vote Labour.
This article, on being both black and Jewish in this election, expresses it all far better than I can:
www.theguardian.com/commentisfree/2019/dec/11/jeremy-corbyn-boris-johnson-antisemitism-hostile-agenda-people-colour