For Israel, WMD's ie Chemical weapons were the only issue.
First, Syrai does not have S-300
You are overestimating the usefulness of Iskander and S-300.
Iskander is a grorified SCUD missile and even primitive BMD systems ( primitive compared to today's ) could intercept it. On top of it, Israel is a pioneer in field of missile defense technology. This system does not poses a threat which
Arrow could not handle.
Regarding S-300, People here forget that it is a cold war system that Russia no longer uses as a frontline Air defense system(they have S-400) and there are ways to get rid of S-300.One of the method is to use one of your plane to loiter outside the range of S-300 missile at higher altitude while using using other plane to infiltrate deep by low flying or by using terrain to mask one's approach. The hidden aircraft fires it'd missile which is then guided to it's target by the loitering plane.
This is one of the method.Other's are anti-radiation missiles and terrain hugging Cruise missile strikes. ( S-300 cannot intercept an aircraft
(Cruise missile is an aircraft) at altitude of less than 50 m).
