Sorry, you completely missed the point of the analogy. The point of the analogy is that within the realm of the browser Javascript provides the most natural substrate for compiler code generation, much like assembly is the most natural target for code generation in many other environments. It's a pragmatic point not a theoretical one. It has almost nothing to do with the specifics of either Javascript or assembly language as mediums for writing programs. You're overanalyzing it to the point where I have to think you are trolling.

(Disclaimer: I've worked on compilers that target both assembly language and compilers that target Javascript)