curious. - I don’t know why the picosecond didn’t copy over from my post. Another mystery.
As to your question - I won’t venture an answer as I’m not the author of that material. The point the author was making is that a switch indeed introduces measurable jitter.
Before this study, many believe they heard improvements from upgraded switches. I acknowledge it could still be placebo, but at least we now can begin to consider potential deleterious effects of jitter with some supporting data.
The point I was trying to make is that it’s not worth spending time on as it’s a circular argument. A point you seem to find unsatisfying.