You are right, but it is almost impossible to do so. Frogs in the wild do not need supplements because they eat hundreds of difference types of food that have a large arya of nutrition. We cant do that in captivity. some of us are lucky to be able to feed 3 types of food. So supplements are a high recommendation whether you gut load or dust. Now gut loading doesnt have to be a brand name product either. If you feed your crickets lettuce and oranges they will be able to provide a sufficent source of calcium.