WL is similar to Python: it is predominantly an interpreted language. Where that becomes a problem, we wrap other libraries, or move small chunks of code into a VM to avoid the cost of the evaluator, or to C and then compile that (a rather roundabout way of doing things that will improve when we move to LLVM).
But as I said before, CPython is a close analogy for where we are at. What we don't have yet is the equivalent of PyPy. Still, if you were to make this kind of dismissive critique against the maintainers of CPython, I think most people would find it kind of silly.
Also, one should note that this documentation was written during an era when perhaps most of Mathematica's user base were people doing math, for which the primary use for compilation was things like plotting, numeric solving, and so on. The language of the tutorial reflects that heritage. At this point we should probably rewrite it.
If there is something like a Wolfram Language, it better should be documented like other 'programming' languages. The core of the language is underspecified. Even the small Scheme standard is much more rigorously specified, including an attempt on a formal semantics.
But as I said before, CPython is a close analogy for where we are at. What we don't have yet is the equivalent of PyPy. Still, if you were to make this kind of dismissive critique against the maintainers of CPython, I think most people would find it kind of silly.
Also, one should note that this documentation was written during an era when perhaps most of Mathematica's user base were people doing math, for which the primary use for compilation was things like plotting, numeric solving, and so on. The language of the tutorial reflects that heritage. At this point we should probably rewrite it.