Agreed. In fact, Cardigans are known for being relatively insensitive to what they're fed. They can do well on some pretty junky ****, probably because they're a relatively primitive breed from a very harsh place. And they were farm dogs, not pets, and expected to get by on whatever. And there are some people who feel they do best with some filler in their food. Mine does great on a more or less filler free diet, but some people do clame they need it.
I've fed raw for years and I'm still annoyed by the "oh it's magical and natural!!!" I feed raw because 1.) my potential chubster Macky maintains a healthy weight without having to be starved on it - that's how I got started feeding raw. 2.) My dogs seem to thrive on it, short and long term. 3.) I just like feeding whole, unprocessed foods and knowing exactly what goes into my dog's diet. 4.) Dental benefits, gotta say I do love this aspect. The vet can't believe Macky's 7 and never had a dental, and isn't anywhere needing one. 5.) Give a corgi a frozen chicken quarter, and she won't bark for at least 30 min.
LOL
I think "Mixing raw and kibble gives some dogs diarrhea" is pretty accurate. Just like lots of things give some dog diarrhea when they're suddenly introduced.