Yep, this ignorance is one of my pet peeves. Humans were not hydrophobic until Hammurabi’s codes were written which instilled the universal superstitious fear of water. To this day universal superstition still prevails in the primal subconscious causing that common consensus of the hydrophobia. Just like the common hatred of serpents from the garden of eden, and the tendency to automatically say “Bless you” when someone sneezes and ejects evil spirits. A lot of archaeology and anthropology is still based on deep set subconscious religious superstition.
“I fear water so I KNOW early man definitely feared water, because I am much more intelligent than they were”. Well, maybe not... Maybe your own deep set superstitions are misplaced when using as a prerequisite.
Primates hate serpents. Probably because when they stick their little hands into a bird nest for eggs they could find the snake that had gotten there first.