CAR means Content of Address part of Register and CDR means Content of Decrement part of Register. They were tied to the 36-bits nature of the first LISP machines, with 15 bits to CAR and 15 bits to CDR (plus 2 bits for tags IIRC).
So its not just naming keys in a structure, those had a very low level meaning related the the implementation of the CONS cell structure in hardware.
I agree. And it seems to me that it wasn't language issue, but lack of encapsulation. I also don't find those cons of using CoffeeScript convincing enough. Have these guys tried TDD? If you use TDD you'll probably find accidental overwriting out-of-scope variable in a matter of seconds. Because you should never rely on language syntax.