It’s all about priorities. Israel has made it clear that Shia Iran is their greatest existential enemy. Shia Hezbollah in Southern Lebanon is number two. The Shiite Assad is friendly with Iran and has direct alliances with Hezbollah and Iranian Revolutionary Guard in fighting the Sunni Salafists in Southern Syria.
In my opinion, this makes him a marked man as far as Israel is concerned. Why do you think the IAF bombs Assad’s forces but rarely will attack ISIS and Al-Nusra/Al-Qaeda?
Thanks for the guide to who is evil, bad, and not so bad.