This is probably the least important or interesting thing I could say about the play right now, but since it's also one that's getting lots of coverage let me just say it:
There is nothing even remotely vaguely anti-Semitic about Caryl Churchill's Seven Jewish Children. It is not in support of the Zionist mission, but that's not the same as Anti-Semitism and the conflation of Zionist identity with Jewish identity is one of the many reprehensible aspects of the Zionist movement in general.
You can read it for yourself here. People leveling the claim of anti-semitism against this play are simply trying to shut down conversation and ignore voices that question the rightness of Israel's actions.