because normally back yard breeders don't know what they are doing. They randomly pick 2 bunnies to breed, they don't know their background, they don't always have good homes lined up, they don't always have money for vet bills, they don't always take their bunnies to the vet if they need it. They often breed for money.
There are a variety of issues with backyard breeding of rabbits.
1. There is a serious overpopulation of rabbits. Breeding prevents rabbits in shelters from being adopted and can contribute to their euthanization.
2. Irresponsible backyard breeders often have no idea of the health risks associated with breeding rabbits -- there are many threads here where ignorant people decided to breed rabbits and ended up with sick parents and dead and dying babies.
3. Genetic issues - a truly responsible breeder is tracking their stock and seeking to eliminate health concerns from their rabbits. Randomly throwing two rabbits together does not accomplish this.
Backyard breeding of any animal is irresponsible, it makes me angry when I meet people who do it. :/ There are so many animals already in the world that can't get homes. I came across an article that says rabbits are the third most euthanised animal in the US - I assume the first two are cats and dogs. Also where I live (New Zealand) sometimes people dump animals and, while it's unlikely that domestic rabbits will survive in the wild, we do have a real problem with wild rabbits as we have so much of our economy based on agriculture, so anything that adds to that is definitely not good.
I know there are people out there that have a strong drive to have the experience of having a litter of baby animals around, often they say they want their children to have the experience. All the preaching we do and the vets do just doesn't seem to take that drive away, no matter how many homeless animals there are out there. I think it would be wise to encourage these people to join rescue organizations so they can foster baby animals instead of breedin them. Then perhaps they will understand. I think they need to experience the problem before it sinks in.
i never had to have experience with breeding we grew up on a farm i have experienced more babies that i would care to. from sheep, goats, cows, cats, pigs, horses, chickens, and such. It isn't a good experience to see deformed, dying, sick, baby animals. it doesn't happen often but still happens.
I can understand why some people like to breed animals, but it is not for me. All of my pets are spayed/neutered and I have spent plenty of my own money on spaying and neutering rabbits that I have rescued.