Well, while rescuing animals is wonderful, it is not holier than other forms of good pet ownership. It’s a huge risk, for one. An animal’s past can determine his behavior. Many households have children or have visiting children. No one needs or wants an animal previously traumatized to react with violence one day when he has a trigger from his trauma.
Choosing a purebred or known hybrid puppy allows you to raise your own dog and have him behave the way you wish, with love and affection and good training. You can choose genetic traits that work for your family and lifestyle. Choosing a hybrid reduces the poor overbreeding of straight breeds. (Hybrids are like labradoodles etc where the dog is never a result of inbreeding but is a crossbreed and still has known genetic look or personality but misses illnesses and genetic weaknesses). Obviously the best bet for buying any kind of breed is their breeder.
However, pet stores have been infamous for buying poor quality dogs from disgusting puppy mills. So getting a cute mutt from a store is probably better than encouraging puppy mills (which will still operate illegally for lab animals etc).
Hybrids aren’t healthier, that’s an old wives tale.
We have a dog and a cat, both rescues. The cat was just a kitten, a little fuzzball found on the side of the road. No one claimed him and he ended up here.
The dog was a stray as well, not tiny but still a puppy. He too went unclaimed and ended up with us.
Neither one has had problems from past trauma that we have seen. Well, the cat can be a PIA at times, but that’s just being a cat.
All that said, you make a good point. I’ve also seen plenty of dogs which aren’t abused but which have been allowed to develop bad habits. Some of them would be very unpleasant to live with.