The Security Council has adopted an arms embargo as well as other provisional measures exercising its political power to keep the peace. The ICJ is a court of law, not a U.N. political organ. The court cannot overturn political decisions taken in the U.N. Security Council and has so far never gone against Security Council resolutions in its rulings. There is no hierarchical relation between the two U.N. bodies, so you cannot appeal against a Security Council resolution at the court. The council is not subject to the court because it is not a state. It would be inappropriate for the court to order different provisional measures.