This is great example of virtue-signalling and rationalizations.
No, typing speed is irrelevant related to content quality. Think of poetry - it is all about finding the right word rather than committing them into writing.
He just plainly typing too much - a thick book fallacy. Truth does not require lots of verbiage, on the contrary, it requires a short, clean, precise, adequate "just right" formulation.
That piece of text in in the link could be reduced 10x without losing anything meaningful (which is very sparse indeed).