That's a terrible argument. I still write and read Python with libraries that use C (for example: the entire standard library). If you want an example that fits the point you are trying to make, consider Lua/C, where you _can_ mix the two easily.

The point is still flawed, though - CoffeeScript is not JavaScript, and I have no interest in learning it (I'd rather spend the time learning to write better JS myself). I, and everyone else with my mindset, has their time wasted by this mislabelling; we would not have clicked through if the title said CoffeeScript.