The thing about fair use is that there’s nothing a license can do to prevent it. After all, that’s the whole point of fair use: to say that there’s valid reasons to use pieces of IP without regards to their licenses.

So, if the courts find in Microsoft and OpenAI’s favor (which remains to be seen despite the many armchair lawyers here), your license would mean jack squat.

They don't aim to. The problem is really just accreditation. If copilot copies a chunk of code for you, chances are the original author was perfectly happy for you to do that, and you put their name somewhere in your credits. Copilot copies the same code, but scrubs the original author. It may also be copying code that was not ok to copy but that's a seperate even worse issue.