Why do people say bread is bread, when there are different kinds of bread?!
Why do people say bread is bread, when there are different kinds of bread?
Wheat, white, potato, pumpernickel, etc.
Answers:
"Bread" is the generic term, inclusive of all the more specific types. It's the same linguistic logic as using "dog" as the generic term for the more inclusive types "dachshunds", "dobermans", and "chihuahuas".