If I copy the code line by line with my eyes and keyboard, then the code briefly doesn't exist, but the instructions to recreate it do. Copying it is then a two-phase process: first I read the code, then I type it in. It is clear that I'm allowed to look at the code, so it's the action of typing it in that violates copyright. In the same way, distributing Copilot doesn't necessarily break copyright, but using it may.
Copyright was established (much) after the printing press made copying so easy.
We now need protection against machine learning (learnright?) because the only way to not work for Microsoft for free now is to not release your source code... so not open source. Remember when people said that Microsoft changed its mind on open source?
https://twitter.com/stefankarpinski/status/14109710611816816...
It is still quite rude to do that though.