The term "blood libel" gets thrown around very loosely. Historically it means the lie about Jews being supposed to kill Christian Childrento use the blood as part of a secret Passovr ritual - a version of it is incorporated in the ballad Little Sir Hugh.

It's been a horribly persistant libel over the centuries, and it still gets peddled. It's been suggested that it's a distortion of a libel against Christians by Romans, based on rumours about the Eucharist. It's a lie that should always be challenged.

But the term also seems to get used in a very different sense, as an accusation against allegations that the Israeli government or its agents have been responsible for atrocities against civilians. That seems to me an unworthy and quite unjustifiable extension of the expression. Sadly it seems that such atrocities have taken place, and have nothing to do with "blood libel" any more than they would if it was some other country or people being accused. It's not a blood libel against Palestinians to say thta some of them have caried out suicide bomb attacks, it's a sad truth.