Originally Posted by aka123

You make stuff up. Pure bred is not synonym for inbred, it means specified race and dogs matching those specifications. Breeding might bring inbreeding if done wrong, but they are not synonyms. Also the so called unwanted dogs are bred dogs too, as they are dogs, not wolves. Dog is a breeded specie.

Why I should take some mixed race dog for example as a hunting dog, as I have no idea how it will work?

Also rescue dogs are not any better if it still supports some bad animal treatment. For example second hand slave is not any more ethical than first hand, it still supports slavery. If you buy your dogs from a good breeder, you can influence to the conditions of those dogs and what kind of dogs they are. You don't get that vote by getting rescue dog.