As I read it, the point of the article is to explain how you deal with decisions when the "captain" can be anyone in a group, and not some designated hierarchic

As I read it, the point of the article is to explain how you deal with decisions when the "captain" can be anyone in a group, and not some designated hierarchical leader. It's not democracy per se: for instance a designer can come with a proposition to give people a chance to review it. In the rafting example they're basically saying "we go right", and will do so if nobody shouts "there's a cliff on the right".