They probably mean that the canis lupus columbianus were hunted to extinction (which I'm guessing they were, because we no longer have any canis lupus columbianus listed anywhere.. )
They aren't listed anywhere because they are no longer considered their own subspecies. They are lumped with another subspecies. Some breeders of high content wolfdogs mention having British Columbian Wolves though.
That site has alot of incorrect info as well and also no sources listed. For example, it says Great Plains Wolves are extinct,but they still exsist and are in fact one of the most common subspecies in North America. They are the wolves found in Yellowstone National Park. Also,on their pseudo-wolves page, some of those are real wolves, i.e. Red Wolves,Dire Wolves, Ethiopian Wolves(though is still some scientific debate on whether to consider them wolves or jackals), and I'm not entirely sure why they listed domestic dogs on that page,but dingoes on the other as both are subspecies to the gray wolf yet not exactly wolves technically.
Exotic Wishlist: high content wolfdog or wolf,low to mid content wolfdog, Coyote, Coydog, Black-backed Jackal, New Guinea Singing Dog, Red Fox, Gray Fox, Mink, Raccoon, Coati,and Kinkajou.
Domestic Wishlist: dogs, cats, ferrets, donkey, mule