Will Emacs make me a better programmer?
First let me say, I am a self professed true believer in the cult of Emacs.
That said, the blogger is nuts. You write in what you find useful. I find that Emacs helps me, mainly because I spent my college years pre-paying the start-up cost of learning how to modify it to suit my needs, and modifying myself to its needs.
But other people do things differently, and as they say "That's OK".
He (Steve Yegge) has elaborated on this, in bits in pieces, in other postings of his. http://steve-yegge.blogspot.com/2008_04_01_archive.html is probably the most comprehensive, but the info is buried in there since it's on a tangent to the main subject.
I guess to summarize: the programmers who are merely good or competent will pick up an IDE and get to know it really well, and maybe do decently enough in it, but they'll restrict themselves to what the IDE provides for them. In other words, they adapt themselves to the IDE. The great programmers, on the other hand, will adapt their environment to suit themselves, in such ways as writing scripts or their own tools, or extending their tools. And to that last point, not only Emacs is the most extensible environment there is, it is also the easiest environment to extend there is, and it is the environment where you reap the most benefit from extending it--your extensions integrate into Emacs like they are stock features, and so your future extensions may build upon your previous ones (positive-feedback-loop kind-of thing).
The best programmers use vi or emacs, because the most experienced programmers are the best, and 20 years ago, there wasn't much choice except vi and emacs.
After having started with vi (ca. 1987) on a machine with a very slow text terminal, I converted to (GNU) Emacs after a few years (on a faster machine), and used it almost exclusively for nearly 10 years.
Emacs was the first truly integrated development environment - the whole edit/link/compile cycle could be controlled in emacs, and you could roll your own for whatever compiler you used.
Nowadays, IDEs such as eclipse are even better integrated (to be honest: emacs sucks at graphics), but Emacs is still one of the best environments for "pure" text editing.