What is mutual harm?

Fruit producers don't eat skinless fruit;
Flour producers don't eat overly white flour;
Seafood producers don't eat lively jumping fish;
Farming producers don't eat meat that grows too quickly;
Vegetable growers don't eat out-of-season, overly beautiful vegetables;
Hotpot base makers don't eat hotpot with overly red color;
Marinated meat producers don't eat meat that still looks fresh after being stored too long;
Barbecue vendors don't eat skewers that are too heavily marinated;
Beverage makers don't drink delicious drinks they don't like;
Milk tea makers don't order the cheapest milk tea;
Snack producers don't eat pastries with too long a shelf life;
Frozen food producers don't eat frozen foods for long periods;
Food additive manufacturers, always check the ingredient list before buying;
Health supplement makers don't believe in "cures all diseases";
Weight loss product makers don't touch "lying-down slimming gadget";
Cosmetic producers don't blindly trust luxury brand names;
Medical aesthetic clinics don't easily undergo projects they promote themselves;
Live-stream sales hosts don't buy the hottest items in the live broadcast;
Financial professionals don't believe in guaranteed profits;
Because everyone knows: in their own industry, which things are the most taboo.