> I removed comments from JSON because I saw people were using them to hold parsing directives

Java has not been destroyed, nor any other language that uses injected behavior. Ironically, applying parsing directives are basically another tool being run (similar to a linter) so I'm not sure what he's even getting at when suggesting running yet another tool. This just complicates the ecosystem and is part of what makes javascript seem so primitive in use and syntax. Features that are counterproductive for poorly considered reasons.