No junk has been added into JSON - the specification hasn't changed to accommodate those features.
Unless you need to use the feature, you don't need to know anything about it, which is a huge benefit for the majority. XML almost encourages programmers to use unnecessary features.
When an application domain chooses to add a feature (say JSON-LD) then there are advantages to that mixture over XML. Where XML is better, it is often chosen instead.
That depends entirely on which parser you’re using. People have wanted comments so badly there are parsing libraries (and proposed revisions to JSON) that include comments. And sometimes those comments are used to provide processing directives.
> Suppose you are using JSON to keep configuration files, which you would like to annotate. Go ahead and insert all the comments you like. Then pipe it through JSMin before handing it to your JSON parser.
Unless you need to use the feature, you don't need to know anything about it, which is a huge benefit for the majority. XML almost encourages programmers to use unnecessary features.
When an application domain chooses to add a feature (say JSON-LD) then there are advantages to that mixture over XML. Where XML is better, it is often chosen instead.