When I took my oldest river-rafting about twenty years ago, I took us off a raft that was filling up with Korean tourists and moved to an all-American raft, and told him why. They were incredibly badly behaved and ignored the raft guide. Theirs was the only raft which wrapped on a rock, filled and dumped them in the fast cold river. The males ignored the females and tried to save themselves first. This is normal.
My son and I were real careful not to let them grab us while fishing them out - we stuck oars out for them to grab and them let them pull themselves over the side of our raft rather than helping them. Other people in our raft who were less cautious were pulled into the river trying to help them, until our guide said to let her do all the rescuing. The other raft guides did the same.
Your post is an eye-opener. Never would have thought that would be the case.