I have discovered that there are many people in the dog world who wish to be classified as a dog trainer even though they have no idea what they are doing with a dog. For all I know they fit that description.
You might be right there as I dont know these folks just pulled a page off google. I do however know some good trainers out your way that do snake training in this way. I have done it as well, I am not a pro tho just been doing dogs for 50 years. Many of my pups are now FC MH etc.
Do it right and the cats will be OK, my 6 dogs leave my cats alone and they hunt fine. I also use in ground electric fences to keep them in a 5 acre area.
I have found that if you bring in a kitten the dog may adopt it and you have no issues, bring in a dog and have full grown cats you will have issues. Gotta teach the dog cats are off limits.
Good luck to the OP, hope you can get this fixed before you come home to a dead cat.