Didn't the guy end up dying? By the time she got to him, he was likely too weak to fight, or was dead already.
And the result of something doesn't indicate all possibilities. Had someone gone out sooner, maybe they would have been swept under/away, or would have been used for a buoy by the person drowning. We don't know what would have happened if someone had gone out sooner. What we do know is that these regulations are put in place in order to address as many variables as possible.
Would you be so willing to have one of the untrained, unequipped officers dive in to fish the guy out if there had been a storm raging? Or if the man was clearly armed? If he had committed some violent act before ending up in the water? If that particular body of water were known to sport many dangerous riptides or harmful wildlife (sharks, piranha, venomous jellyfish, poisonous corral)? Or if we knew that the officers at the scene, not being trained or responsible for water rescues, were actually very weak swimmers?