Earlier quoted context omitted.
The Gameboy color hardware can be simulated on a desktop computer in a browser, in javascript. Does that make desktop computers more primitive than Gameboys?
@viraptor and so we can see that we must take into account more than just whether one can be simulated on another, we must take into account /expressiveness/, or level of complexity as well! In theory, you could simulate prototypes with classes too. You have to be able to, or else it wouldn't be possible to write an interpreter for a language which supports prototypes. The question of "can" and "can't" then, in the c…
If I really wanted to prove a point, I could make a string behave like an array. But that would take even more work because an array is a very flexible tool used for a variety of low level purposes.
Therefor, according to your argument, a string is a more primitive data type because it takes more work to make a string act like an array than it does to make an array act like a string. This goes in direct contradiction to the actual definition of a programming primitive.
Back to the original poster's quote, "JSX offers a solid class system much like the Java programming language, freeing the developers from working with the too-primitive prototype-based inheritance system provided by JavaScript."
He is quite clearly addressing a specific case here, which is programmers who want to use Java-like classes when developing in Javascript. A lot of extra work is required if you want to make a Javascript prototype behave like a Java class, with inheritance, etc. So in this context, it is obvious that Javascript prototypes are "too primitive" for the task at hand.
Similar to the way that strings are, in fact, arrays with lots of extra functions for frequently repeated, string-related tasks, JSX classes are JS prototypes with a lot of the oft-repeated boilerplate code done for you. I'm not sure how to make it more clear how the chain of "primitiveness" flows in this case.