Imagine a web scraping robot that just grabbed textual news articles and spit them out verbatim to searchers (without giving credit or linking to the original). That is obviously copyright infringement, even though it is done by a robot.
Now imagine it does slight modifications to the text, using a thesaurus and maybe a bit of AI. It might substitute "is able to" for "can", or "frequently" for "often", but otherwise everything is left as is. Is that "machine generated"?
Same goes for a hypothetical bot that scrapes existing music, and after listening to "He's So Fine", comes up with the melody for "My Sweet Lord." (as per the famous George Harrison copyright case from the 70s) It isn't off the hook simply because a machine was involved. If it truly "learns" what makes a good melody, and uses that to generate a very different melody (that might be equally similar to a dozen different songs), that's different.
There is a full spectrum between simple bots that copy verbatim, and something that "deeply learns" and then writes a new article, or generates new source code, or writes a new melody, or whatever.
I don't have a strong opinion on GitHub Copilot since I haven't really studied what it does and therefore I don't know where it lies on that spectrum, but this article is not useful if the author doesn't really explore the nuance, and treats everything as absolutes.
(and I should say, I am very much of the opinion that copyright law as it is, is hopelessly broken, and I am always glad to see things like Copilot just so we can see it demonstrated why. But that is veering off topic...)