To some, the dietary regulations of Leviticus and Deuteronomy are exemplars of what rabbinic tradition calls a ḥok (literally, a statute)—a Divine decree whose rationale is unintelligible to mankind, and known only to God himself. Natan Slifkin argues that, on the contrary, these dietary laws have ethical meaning, if one understands ethics not “in the narrow Western sense of not causing harm to other people,” but in a more expansive Judaic sense:
The Torah (Leviticus 11:45–47) explicitly states that the dietary laws are about k’dushah, sanctity. This [term] relates to the concept of separation—restricting oneself from freely eating whatever is available, and also separating the Jewish nation culturally from other nations, so that they survive with a distinct identity and remain focused on their mission. And there are themes we can clearly detect in the Torah’s choice of forbidden species. These include a general avoidance of eating predatory animals and birds (conduct we do not want to internalize), an avoidance of eating “aberrant” creatures (such as bats), and avoiding creatures that generally elicit disgust as food items, such as reptiles and most insects. The Torah even explicitly and repeatedly uses the term shekets, “repulsive,” with regard to eating insects.
Avoiding eating disgusting creatures is an aspect of morality. The social psychologist Jonathan Haidt wrote a famous and fabulous book called The Righteous Mind, which is . . . an excellent source of insights into Judaism. As he explains, there are many different spheres of morality. One of these is sanctity versus degradation, which is shaped by the psychology of disgust and contamination: “if we had no sense of disgust, . . . we would also have no sense of the sacred.” The idea is to reinforce the sentiment of disgust in order to encourage moral behavior. Haidt explains that it underlies religious notions of striving to live in an elevated, more noble way.
But what about all the many millions of people in the world for whom eating bugs is perfectly normal? . . . The answer is that [doing so] is indeed not objectively disgusting. . . . But even disgust that is culturally subjective becomes religiously significant.