I don't think a person needs to be a genius to do well in Lisp. As a long-time C and Fortran and Python programmer (and many other languages) it took a long time for me to adjust to the different way of thinking necessitated by Lisp.
Also if Copilot or LLM write Go code, why do we think it can't write Lisp code?
I've dealt with code in many languages that were written by "geniuses" and find that they can be as hard to understand as any Lisp program. Often this depends on the problem being solved. There is a story about Donald Knuth and Edsger Dysktra working on a problem that required no less than four stacks to process. (If memory serves correctly, they found a solution using iteration rather than stacks that was much clearer to understand.)
The solution of Sudoku by Peter Norvig (https://norvig.com/sudoku.html) is a bit of a genius solution but it is written in Python.
It would be a disservice if the article's distinction of smart vs average were to dissuade anyone from learning a new language.