A lot of open-source software uses copyleft licenses like GPL. If a company uses that code to build its own products, then some or all of their new code may also become open source. This is an important part of how open-source projects stay open. Organizations like FSF have taken big companies to court over this and won.

AI companies trained their slop-generators on that open-source code. In many cases, it will reproduce it line-for-line. But courts currently hold that the generated code is no longer subject to the original copyright restrictions. It’s nearly impossible to publish open-source software without being scraped for AI training.