My dad teaches a world religion class and does a unit on religious restrictions (kosher, halal, etc.). He says one of the hardest things to get across to people

My dad teaches a world religion class and does a unit on religious restrictions (kosher, halal, etc.). He says one of the hardest things to get across to people, even non-religious people, is that rule systems like these are not about practical considerations, they are about defining who is "in" and who is "out". In a time where religion is no longer analogous with ethnicity, this is just not something people really understand anymore.