Stop imagining them in their underwear.

I work with someone like that. He hits a lot of keys in a very short period of time... but almost half of them are the backspace key, because he almost never hits the key he wants to hit.

It sounds like he's getting a lot of work done. If you look over his shoulder, you might find out he's spent the past five minutes trying to scp his editor's configuration file from one machine to another.

You think C++ is more concise than Java?

It is to laugh.

Perl... now Perl isn't always terribly friendly on a touch-typist. But maybe that's just because I haven't mastered the opposite-hand-shift like I should.

A moderate typing speed suffices. Say, oh, 30wpm, or thereabouts?

If you're not typing at a reasonable speed, you're going to have an incentive to shorten variable and function/method names from something reasonable to something cryptic. You're going to avoid typing documentation, or worse, propose that your cryptic POS code is 'self documenting'. You're going to be an unpleasant partner if you end up pair-programming. All this means you're not only affecting /your/ productivity, but you're now negatively affecting the productivity of others -- all because you're too damn lazy to learn to type.

It's not really about raw speed. Typing should be an unconscious reflex... you want words and symbols to appear on the screen, and they should do so, without you having to think about it. That way you can think about the problem at hand, and not about the act of entering the code to solve the problem.