I don't think the article said what the snake was. From the pictures, I'd say it was a timber rattlesnake, Crotalus horridus. As rattlers go, timbers are pretty middle of the road regarding size, amount of venom, venom toxicity, irritability, etc. Timber rattlers and copperheads are the usual venomous snakes used in those ceremonies because they are native to the area and easy to catch. There would be a lot fewer of those religious snake handlers if they used diamondback rattlers (big and irritable) or mojave rattlers (high venom toxicity).