Ok, I concede, the story is true.
But considering a simple climbing harness is rated to take forces of several thousand kilos, and lifting strops are available off the shelf, that will hold 12 tons, it's inaccurate to say that the harness itself could not hold the weight of a larger chap.
There are clearly other factors at play, it would be interesting to hear from a helicopter rescue worker whether or not they'd let a fat bloke drown because of health and safety rules.