I don't use lisp often enough to have played with getting GPT to lisp with me, but I have played a bit with getting it to read and write Datalog (which I suspect is even more scarce in The Pile dumps). It's ok at recognition but misses details. I haven't seen it produce much of value yet. But it can write JavaScript for days, and has no problem balancing parentheses and brackets there, even without compiler/tree-sitter support.
If I had spare experimenting bandwidth I would look into whether fine-tuning for Lisp format and conventions would show a significant boost in performance..
Any pressure you feel to adopt python is not because it has detected you enjoy python, it’s because it’s global training data skewed to python.
Its a huge concern but, not this article’s concern I think.