"We can replace Rhodesian's with king Charles spaniels, with syringomyaelia, what happens to them?"
A world full of shit quite frankly...but they're a breed that although lovely and fantastically suitable as household pets for most people I actively discourage people from getting because of the health issues.
I don't particularly care whether someone's dog is a pedigree, a mongrel or a cross...I've owned all 3.
I care about things like bad breeding practises that affect animal welfare and indiscriminate selling which again affects animal welfare.
If you have the perfect dog for you and from a good breeder, fantastic, because you're happy and the breeder is doing the right thing by the dogs and won't be adding to the rescue population.
The issue is that there are thousands of breeders, crossing any old poodle without health tests with any random dog they can find and claiming they'll be non shedding and healthy and the best of both breeds and then they don't take them back when that isn't the case.
It happens with pedigrees too, but crosses attract those sort of breeders even more because it's higher amounts of money and they're popular.
It's not the dog's fault, but it is partly the buyer's fault for not doing enough research...mostly though, it's the breeder's fault - but they don't care, potential buyers might, so people do their best to inform the public about what the issue actually is.
Also, separately - the names big me, because they don't work logically, lol, but that's my issue.