[RawFedDogs]

Why do these people keep insisting that dog's need carbs?

Because they buy the hype from the dog food mfgs. Dog's do not need carbs because fat DOES supply the energy needs of ANY dog. Look for authorative sources for the recommended daily allowance or for the minimum daily allowance for carbs. You won't find any anywhere?

Is any of this true?

No

Do carbs provide some energy?

Yes, carbs provide energy but fat supplies all the energy a dog needs. If you have a dog who is in some kind of competition that requires a lot of energy, simply feed more fat.