The community cohesion aspect is very well described in this article of Nicholas Taleb "How to be Rational about Rationality", especially with regards to the Je

The community cohesion aspect is very well described in this article of Nicholas Taleb "How to be Rational about Rationality", especially with regards to the Jewish communities: ... Jews have close to five hundred different dietary interdicts. They may seem irrational to an observer who sees purpose in things and defines rationality in terms of what he can explain. ... But it remains that whatever the purpose, the Kashrut survived approximately three millennia not because of its “rationality” but because the populations that followed it survived. It most certainly brought cohesion: people who eat together hang together. Simply it aided those that survived because it is a convex heuristic. Such group cohesion might be also responsible for trust in commercial transactions with remote members of the community. https://medium.com/incerto/how-to-be-rational-about-rationality-432e96dd4d1a https://medium.com/incerto/how-to-be-rational-about-rational...