That's like the argument that used to be made against wearing seatbelts in a car. Despite all the lives saved and injuries avoided by the use of seatbelts, someone always wants to point to the rare exception where someone was hurt or killed by them. My son was saved in a roll-over car crash by his seatbelt, and the only death I've seen on a sailboat was from a person who wasn't lashed on when the boat was rolled over in breakers during a storm.
I wear seatbelts in the car and use jacklines,
harness and tether whenever I'm singlehanding the boat or, with crew, in anything more than a fresh breeze, except when racing in local waters, where help is readily available.