I saw a few large ones in the Everglades. They feel safe in the water, and reasonably safe basking near water. An idiot friend of mine had to touch one, once. About an eight footer. As soon as he touched the top of its tail, it dove in the water. The biggest one I saw was basking on a road, and as soon as the car got too close it scrambled and dove into shallow water. The scariest thing about it was how fast it disappeared in what looked like two feet of water. I inadvertently found myself about 6 feet in front of a mother with newly hatched babies. They were between us, so I froze and backed up slowly. An adrenalizing experience.
It is not like he was in the Northern Territories of Australia swimming with salt water crocks.
The only way this guy got eaten by a gator was that he was already dead laying in the water.