People who don't know too much
This sounds to me like a fascinating confrontation between different approaches to religion and knowledge. The judge believes that, without an intimate knowledge of the sources of the law, practice will necessarily be deficient. The butcher sees no use for theoretical knowledge, since his responsibility is practical. An approach still respected by many. In fact, Rav Kook thought it better that the butcher be uneducated.
Daniel Frank has written about another controversy over the credentials of a shohet, this time in the Karaite community of Istanbul (in Hebrew in Pe'amim and in English in the Isadore Twersky memorial volume). There the focus of the controversy was even more theoretical. The practical skills of the butcher were never in question. At stake was his stance on the theological question of how the killing of animals for consumption could be justified. If the slaughterer did not subscribe to the proper opinion, his meat would not be accepted.
Reading the Frank article, I was struck by the high value placed by the Karaites upon this ethical question. A butcher who did not understand why his actions were morally justified would render the meat unkosher. How much more so, a butcher who was unperturbed by the question!
Though such an approach seems nice in theory, in practice it imposed an impossible level of orthodoxy, which threatened to pull the Karaite community apart. The problem was that there were two different schools of thought, each with its own answer to the question. The shohet had an answer, but it wasn't the one that the local authority subscribed to. And that, I think, is one of the laudable aspects of Rabbinic halacha (though some would disagree). The shohet is held responsible to his actions. His beliefs, though important, are not policed.