Of course it is. Currently, Iran is the most problematic of muslims for the Jews, in terms of bellicosity and military capability. Iran is nowhere as beholden to the US as Saudi Arabia is. Syria and Libya are too small and militarily inferior to the Israel. Pakistan and Turkey simply does not have the religious gravitas and stature like Iran. Like it or not, Iran is
de facto the leader of the muslim world. The idea is called 'bandwagoning'. That is when an alliance came to be through voluntary participation out of mutual interests.
Bandwagoning - Wikipedia, the free encyclopedia
And why should the muslims not destroyed Israel? When the alliance is behind a nuclear weapons state and if the military campaign is successful in occupying enemy territory, what use is there in keeping alive the conquered political entity?