RT by @Jerusalem_Post: WHY did Israel's DAVID'S SLING missile defense system FAIL TWICE on same day to shoot down Iranian missiles, leading to a high in Israelis injured in a singl

WHY did Israel's DAVID'S SLING missile defense system FAIL TWICE on same day to shoot down Iranian missiles, leading to a high in Israelis injured in a single day of this WHY was it used in 1st place when BALLISTIC missile defense is for the ARROW?