What is ironic about the Czech dentist elie goes to see?

Which number is main idea? (1) eating habits differ widely from one culture to another. (2) many japanese relish toasted grasshoppers, and members of some brazilian tribes enjoy eating ants. (3) if you find such fare disgusting, bear in mind that many europeans consider corn on the cob fit only for nonhuman animals, and many asians and africans reject cheese because they find it too smelly. (4) it’s socially acceptable to eat dog flesh in korea and horse flesh in france. (5) the thought of eating either offends most westerners. (6) orthodox jews and muslims avoid eating pork, which they consider sinful and unclean, and orthodox hindus—vegetarians who regard cows as sacred—find beef particularly offensive.