That does make it different from mathematics, where there are reasons for the rules (you can't divide both sides of an equation by a value if that value might be zero, for example). But the point is more to suggest that it could be possible to make progress in carrying out and understanding mathematics without understanding some of the formal underlying rules beneath a concept. That seems like a valid point.
The adjective order rules are interesting in that we have to reverse-engineer them from our brains, but aren't consciously aware of them. It's apparently an area of ongoing research why certain orderings are correct. (Maybe there's something about the specificity of the adjective, where the more-specific items are closest to the subject.)
I think the higher-level concern is we can get tricked by thinking we need to consciously master the structure in order to be fluent, vs. letting our brain's pattern-matching skills do some of the heavy lifting.
I like the view that this is an open problem and an area of active research, much more than the more conventional, lay-person settling of the issue as "developed an ear for the language" and that's the end of it.
The impressive work of people like Steven Pinker and Chomsky (in his actual academic field) is to look very carefully at different ethnographic groups, and the larger cultures those groups are embedded in. By doing so, finding groups isolated enough or with a materially different context, such that they don't exhibit the same patterns.
The title of the article felt like a bait-and-switch, I guess. When I realized it was on betterexplained, it did make more sense that it was ultimately about mathematical reasoning. No worries!
It's been said (citation needed) that phrases like "tick tock" and "see saw" are in those orders because it's a high or hard vowel before the low or soft (e.g. "tock tick" sounds weird). Maybe that is why "little old" lady sounds more correct to us? I don't know. But the article goes off to draw a parallel to mathematical intuition, and leaves the original grammar problem unresolved, in my opinion.
Incidentally, I usually _really_ like the Better Explained articles.