Mixing a borneo and a ball is mixing species. Mixing a pug and a poodle is mixing "morphs" of one species(the dog).
There's no real difference genetically in making a "puggle" than making a "bumblebee", since both mix seperate distinctly bred lines.
The REAL LIFE difference is in breeding dogs when many dogs are being put to sleep in shelters. But then you get.. why breed ANY dogs? It's a large can o worms to breed any dog.. whether purebred or not. Why not restrict breeding to only the very prime healthiest stock of purebred AKC breeds? Well.. because not all breeds are recognized by AKC. Some people prefer non-purebreds thinking purebreds are all inbred. Some like this.. some like that.
If someone breeds a litter of pups, correctly cares for parents and pups, and sells them into a good home, then I see no moral difference to that, than in a purebred breeder doing the same. There are many purebreds in shelters too!
That said, the ad is "clearly to me" for a mill type organization, since a family should not need that many dogs that they are advertising for, nor that many different breeds.
Why not charge big bucks for "mutts"? If someone will pay it, then charge it. Maybe that mutt will have more value in their eyes if they pay a big price. The issue is normally that people then try to breed THEIR dogs.. thinking they will make big money.. then they skimp on the care of the animals.. or skimp on the checking out the buyers...
Well.. another long ramble.
The big difference to me is that snakes are solitary by nature, and prefer to not have contact and socialization for the most part. Dogs are more needy, needing care and exercise and attention and affection and training. Can you keep 50 dogs for breeding and give ALL of them that? Now.. can you keep 50 snakes and give them what they need? Probaly so.
Unless you walk your snakes with that ultra cool snake walker of course...