Things Are Halal Until Proven Haram?
This is the only logical conclusion. There can be only two situations: one you mentioned and the other opposite to it, that everything is forbidden except for what is declared allowed. Since the second does not exist, the first is proven. The same is the actual situation. What kind of food and actions are haram and what is their illat are described in the Quran, if anything falls in these categories, that is haram, otherwise, halal.