Somehow Israel having 400 nuclear warheads and a determination to destroy the government and unitary state of Iran is a force for good, but Iran with no nuclear warheads and a rhetorical tendency to dismiss the permanence of Israeli statehood is a force for evil.
Sneh thinks that an unchecked Iran will dissuade further Jewish resettlement to Israel, deter Jewish family holidaymakers, and cause young Israelis to seek opportunities elsewhere. Frankly, if Sneh's fears are well grounded then Ahmadinejad is correct that Israel will fade away in the sweep of coming historical, geopolitical and demographic changes.
I'm neither Israeli nor Iranian, neither Jewish nor Muslim, and I don't much like either country's leadership. That said, Sneh and his neocon, zionist ilk scare me much more than the mullahs.