I have`nt said there are no unethical breeders of purebreds, there certainly are, they are every bit as bad as all crossbreed breeders. There is no reason to breed crosses, they are a money making resource, nothing more. Health testing is even claimed for crosses as making the breeder `ethical` however tests for one breed do not correspond to the other, there are many well known crosses which now have hereditary diseases of their own because of the mixes, and skeletal issues because of dogs of unmatched skeletal build - like one of mine has, she is of a crossing deliberately churned out as a designer type...

So no it`s not a rubbish statement to make, the only people imo who should be breeding are those who breed same to same, [ as it`s the only way to have any chance of knowing what size and traits are likely ], are careful about the lines involved, fully health test for all known hereditary testable conditions, sell with contracts, and take responsibility for the life time of the pups they have bred should any of them need help including rehoming at any time.
Anyone doing any less - yes including those breeding purebreds - are unethical.