I think the point was to compare the reasonably simplest idiomatic examples in the various languages. For example, the C++ example used `std::unordered_map` even though that isn't necessarily the fastest possible hash table for C++ for even general purpose jobs, let alone specific ones.
Of course you could write significantly faster implementations in C (and probably in the other languages) by writing data structures from scratch especially for the job (and memory allocation strategies and maybe other stuff), and if you're the author of wc or grep then that is well worth doing because it will be used so many times relative to the amount of time for you to write that code. The comparison of the idiomatic C program vs grep is basically proof of that. But the article seemed to be targetting more typical developers than just want to plug together some common existing components.
