“Trained on billions of lines of public code, GitHub Copilot puts the knowledge you need at your fingertips, saving you time and helping you stay focused.”
“Public code” is doing a lot of work in that sentence. Public is not the same as unlicensed, and much of that code is GPL with conditions attached. The launch page never mentions licenses at all. GitHub hosts the code, trained the model on it and now plans to sell it back to the people who wrote it.