The problem is that they then sell the notes in that database for giant piles of cash.
On top of that, they have no way of generating any notes without your input.
I believe the way these models work is fundamentally plagiaristic. It's an "average of its inputs" situation, not a "greater than the sum of its parts" one.
GitHub Copilot doesn't know how to code, it knows how to copy-and-paste from people who do. It's useless without a million devs to crib off.
I think it's a perfectly reasonable reaction to be rather upset when some Silicon Valley chuckleheads help themselves to your lfe's work in order to build a bot to replace you.
They can switch to a new licence, but it would only apply to future contributions, not what already exists. So if they did that, the result would be multiple forks. MS would need to maintain their own fork for Edge.