"Questions of this kind are a matter for military investigation and are at the core of the military profession," High Court Justice Yizhak Amit noted.
Five other adults were convicted for incitement to violence after footage was circulated from the wedding, held five months after the Duma arson.
The two Israelis were originally planning to jump an Arab citizen but abandoned that idea and decided to attack a mosque instead.
The individual in question threw an explosive at the front door of Temple Ner Tamid in Bloomfield, NJ early Sunday morning.
An unknown masked person threw a Molotov cocktail at the front door of a synagogue around three in the morning.