This sounds reasonable for technical writing, though it's interesting to read McCarthy's recommendation after considering David Foster Wallace's work, where there is a very frequent usage of footnotes.
In his non-fictional essays essays—often in the role of a reporter like in his well-known "Consider the Lobster" for Gourmet magazine [0]—Wallace uses extensive footnotes. This isn't technical writing, though the quality of Wallace's convinced me that footnotes can have a useful place in fictional writing.
> And don’t worry too much about readers who want to find a way to argue about every tangential point and list all possible qualifications for every statement. Just enjoy writing.
From Hacker News discussions (and also speaking to a colleague who competed at a high level on a debate team in high school), I learned the opposite lesson. If there is a weakness in an argument, it's likely it will be pointed out. I've found it important to consider weaknesses in logic and try to anticipate counter-arguments whenever possible, when writing for readers from more technical problems.