Welcome to software engineering, where engineers have extremely strong and fixed opinions about all sorts of fields that are completely disconnected from software engineering.
«A derivative work is based on a work that has already been copyrighted. The new work arises—or derives—from the previous work.
If you own the copyright to a work, you need to be aware that you also have rights to derivative works. If you're considering incorporating someone else's work into your new work, you need to be aware that you may be violating the copyright to the original work.»
Regardless of the nuances of that point, GitHub copilot violates copyright because the content it was trained on still lives in it, and you can get it to spit it out verbatim.
If I were a master artist, my existence wouldn’t violate copyright, but I would certainly be violating it every time I chose to reproduce a copyrighted work for a client.