Well, that's why major TOS changes are accompanied by the option to discontinue using that service. Usually they say that continuing to use the service after a certain date constitutes your agreement to the new terms.

I think we're over here in our armchairs weirdly assuming that GitHub doesn't have any lawyers working for them. I think they know they're legally in the clear on CoPilot.

I'm not at all a lawyer, but in my opinion we observe that the non-automated version of AI-generated works (the act of making art and prose in the style of an existing copyright work based on the artist's observation of that work) is not illegal. The only thing that AI introduces is automation.