State sponsored terrorism from Syria, lebanon. Jordan, iraq, Iran, Egypt. That in my opinion is the root cause, not Just Israel.
Syria, Jordan and egypt tried and failed miserable at conventional warfare, as as we know when around the world, when aggressors fail at conventional warfare, they more often resort to asymmetric warfare, and Israel has been facing that for a very long time. Realize this is war, and the results wont be rosy. Israeli actions will be ruthless, and will only look out for their own interests, and that is the rule of war.... when states dilly dolly with militants, events like 26/11 occur. Arab states will fight Israel till the last Palestinian.