As the other person said, this is largely a strawman. It would be possible to build some kind of black box system, but it's not mandatory. An OK/NOK pizza class

As the other person said, this is largely a strawman. It would be possible to build some kind of black box system, but it's not mandatory. An OK/NOK pizza classifier could do so without telling you why, and in some measures may be more robust than some kind of filter, threshold, morphological rules, pepperoni counter, but the latter will not tell you if something is wrong with the crust. A pepperoni object detector would be trivial and way more robust than whatever classical pepperoni finder you could build.