I never really understood this. This seems to be an oft repeated truism from mid 2000s with little backing it up.
The only awesome thing that JSON did, was lose type information as well. In fact, the only thing that I can see that JSON brought to the table was easier editing by those who didn't have IDEs, at the expense of losing type information.
I can’t just load the file and run it through a parser and get an easily accessible object structure back, I’ll need to navigate the document with DOM or XPath.
JSON with comments (aka JSONC) is in my opinion the best format in wide use today. It has structure and types, but not too many, and not a lot of magic, like YAML has, but for the most complex cases, JSON(C) falls short with its lack of extensibility and inheritance.