You seem to suggest that a background in compiler theory is somehow table stakes for commenting on HN. Since many here are not developers, and many developers don't have a CS degree, a few contextual comments seem appropriate.
If you're commenting about a remarkably clever example of an obscure topic which requires prolonged study to understand, then yes I'd suggest that a background in _______ is somehow table stakes for commenting on a focused discussion of _______ on HN.
"Toy examples" are often the result of long & deep study and practice of a subject, creating something profound which casual observers are not entitled to instantly understand. In this case, it's a very clever compiler: everybody understands this summary, and if you want "a few contextual comments" beyond the source code itself then you know where to get enough information to learn what you need to understand this.
If you don't "get it", and don't want to "get it" on your own, it's not for you.
It's false dichotomy that you either get it or you don't. People will access things according to their ability. Where to draw the line on being inclusive? If some has genuine curiosity and motivation to ask a question and learn, then providing a few lines of overview doesn't clutter the board much and can be a positive contribution.
Exactly, where to draw a line? Explaining a concept of abstract and virtual machines may take a few pages of a dense text, explaining how to parse expressions with precedence may require dozens of pages, explaining C types will add a few more.
So, yes, it's either you're curious enough to dig into a code and find the relevant explanations somewhere else (the said Dragon Book and alike), or you won't get it, regardless of how comprehensive comments are.
