As many have said, the post is complaining about broken parsers and broken data structures, not a broken spec.

An example for this is using a map instead of a key-value-list for object representation

Or float instead of arbitrary precision decimals

Are there more broken json libraries out there, then there are broken XML libraries?

Maybe. But that's not a problem with the spec. Choosing JSON if your use case is well suited is fine nevertheless

Just don't use obviously broken libtaries