You forget, or most likely never known, that a state of war still exists between Syria and Israel. We learnt the hard way not to wait until attacked to defend ourselves. This so called defensive weapon system would make it far more difficult to achieve our goals if we were attacked and this is especially true if they were turned over to Herzbollah a terrorist group which has already proved that they do not care a damn about the lives or welfare of the Lebanese people whom they are supposedly protecting. Herzbollah would once again attack Israel as ordered by Iran if they had the protection against the IAF that this system would provide.
Russian defense ministry: Plane sent to intercept U.S. plane near border on Friday (Reuters)