I personally believe it's unethical to breed cats purposely and, yes, I also believe childbirth to be unethical. There are too many cats and too many people already. Do we really need to add more?
I had nothing against breeders until I moved to my current apartment, where there are dozens of strays, ferals and abandoned cats inhabiting the alley. My partner and I have taken it into our own hands to care for these cats and eventually have all of them TNR'ed since no one else cares, the city least of all... Neither of us were really aware of cat overpopulation previously, hence we have two purebred cats (one Bengal, one Devon Rex) and, while we love them to pieces, we both agreed never to give money to a breeder ever again. How could we ever justify it? It would be beyond selfish when we can literally step outside and pick out a cat that will be just as special.