One of the BLM rangers quoted in the story essential said, hey, these are wild rivers, not amusement park rides. No one designed them to be safe.
It reminds me a lot of skiing. People assume since someone is charging you to do it, it must be safe, but people die every year.
It's interesting to me that no kayakers have died on the Ark. Perhaps because the sport requires a higher level of fitness, ability and experience.