Here's an instructive episode. A Republican official sends an email in which she depicts President Barack Obama as a chimpanzee. The party chairman in the county says the email is racist, and in due course the sender of the email apologizes. She insists she is not in fact a racist but asks forgiveness for her unwise behaviour. She 'didn't stop to think about the historic implications'. Representing a black leader as an ape, it is taken for granted in this episode, is - for historical reasons and independent of intent - racist. No one says, for example, that because the delinquent official had only Obama in mind, her email has no more general significance, to do with how black people are represented.
Now track back a way, to March; and think about a play that shows Jews as variously indifferent to or relishing the killing of Palestinian children; and think about another historical theme, that of Jews as the murderers of children. And then consider Caryl Churchill's efforts to represent her play as not anti-Semitic. I suppose it's too much to hope that she will one day allow that, though her intentions weren't anti-Semitic, her play was and is - and apologize. But whether or not she does, there's still that strange double standard to be explained, whereby anti-Jewish racism is judged by many people according to less demanding rules than is racism of other kinds.
Hannah Rosenthal, whom I featured here some days ago, talks again of some anti-Semitic tropes that are still abroad, among them the blood libel.