Final answer:
The Panel and the Appellate Body reference Article XXIV of GATT 1994 in this case because it is relevant to the measure being discussed. Article XXIV allows for the creation of customs unions and free trade areas, and the argument made by Indonesia involves the suspension of the GATT Exception under Article XXIV.
Step-by-step explanation:
The reason why the Panel and the Appellate Body in this case reference Article XXIV of GATT 1994 is because it is relevant to the measure being discussed. Article XXIV of GATT 1994 allows for the creation of customs unions and free trade areas among members of the World Trade Organization (WTO). In this case, Indonesia argued that the measure at issue suspends the GATT Exception under Article XXIV.
Article XXIV sets out the conditions that must be met for a customs union or free trade area to be considered consistent with the GATT. It requires that the union or area eliminates duties and other restrictive regulations on substantially all trade between the participating countries, while not imposing higher duties or other regulations on trade with non-participating countries that are prohibited under the GATT.
Therefore, by referencing Article XXIV in this case, the Panel and the Appellate Body are analyzing whether the measure at issue meets the requirements of Article XXIV and whether it is justified under the GATT.