It's supposed to be especially dangerous because it doesn't look like a whitewater creek. There's a part where the river becomes narrow enough to jump across and the water appears calm but is extremely deep and fast moving. It's a popular beauty spot and the river can be mistaken for a shalllow stream.

The article is indeed of very low quality, though, and claims of it being "the most dangerous stretch of water in the world" are hyperbole at best.