Sure. You can trace branches to quantifiable roots, but you can’t trace readability. To me, readability means something different than what it means to the author of that article.
This is a good question to ask, if not rhetorical.
When practicing rigorous measuring, quantities need to be quantifiable aspects of the world. For example, you can quantify how much physical space your code or compiled output takes up in memory, and use these quantities as base units to derive others. By branching from a quantifiable root, you can derive metrics such as lines of code or number of CPU instructions, and they’d still retain those quantifiable aspects. Meaning there’s a clear path to the quantifiable root.
Needless to say, readability, as a metric, is not branched from quantifiable aspects of the world. So in a sense, it is still a “made up” metric because (as of today), there’s no way to trace it down to the quantifiable measurements.