E-learning is not simply a medium, though the "e" part of the label does describe Web technologies, which may constitute a medium. What you DO with that medium – e-learning – is however a collection of processes, not a medium. E-learning in its simplest and most generic sense is a technology-facilitated learning process, just as classroom-learning is a classroom-facilitated learning process, and book-learning is a book-facilitated learning process.
Each new medium presents trainers (and learners) with the possibility of creating or refining different processes that, ideally, get closer to the most effective or efficient way of achieving a given learning objective. If that were not the case we'd still be teaching people by drawing with a stick in the sand.
The Internet (the "e") presents opportunities to create and implement learning processes that are different from the processes we grew up with in everyday classroom environments.
The view that e-learning is just classes online may once have held sway, but is now really rather archaic. Those who can't see that are out of touch with how the Web is changing our learning processes and our lives.