Though Mrs. Beech has had a baby outside of marriage that she is now mistreating, she gets angry with her innocent young son simply for having female friends, another detail that shows her religious hypocrisy and her desire to control her son completely. “Blasphemy” is irreverence or scorn directed at God. Jesus
was Jewish, though, and pointing this fact out isn’t blasphemy. Mrs. Beech’s violent response to Willie having a Jewish friend and to mentioning Jesus’s Jewishness thus illustrates her antisemitism and her abusiveness.