pg wrote a Lisp dialect, Arc, with Morris. The Morris from "the Morris worm". These people are at the very least hackers and they definitely know how to code.
I don't think a "not good programmer" can write a Lisp dialect. At least of all the "not good" programmers I met in my life, 0% of them could have written a Lisp dialect.
It's not because Arc didn't reach the level of fame of Linux or Quake or Kubernetes or whatever that pg is not a good programmer.
You can write a lisp in 145 lines of Python: https://norvig.com/lispy.html
Wasn't Arc just a collection of Scheme macros?
(Also, writing a Scheme dialect was a first-semester CS problem set - if you're in a 1980s academic CS environment it was more effort to not accidentally write a lisp interpreter into something, something in the water supply...)