edit: I'm 42, if the matters.
What they mean is that you can't be fast (on a track) without being smooth, and that typically beginner-to-intermediate drivers/riders are trying to be fast in ways that make them less smooth, and ultimately (and counter-intuitively) makes them slower. So the advice is to forget about being fast and concentrate on being smooth. The speed will come.
I do think this has value as an analogy for software, but it is in concentrating on your tooling and methodology - smoother operating will deliver real value faster than just trying to type fast.
In software smooth is fast because you didn't have to bug squash and refactor. But even if it isn't faster, the grandparent comments point was that it doesn't matter as much as being correct anyway.
Most problems in software engineering are caused by only optimizing for speed.