Cleaning up implies they didn't add anything else. This is a major reworking that changes the entire stack.
Do they have to write every single line from scratch again? That would be an enormous waste of time. Even if they started with a completely new repo, they would just copy/paste that stuff anyway. The important bits are all new and that's what matters.
They don't "have" to do anything, nor am I criticizing them. I'm just saying that's it's not completely from scratch like people are saying. If they take this an some sort of attack, it's their problem.
Do they have to write every single line from scratch again? That would be an enormous waste of time. Even if they started with a completely new repo, they would just copy/paste that stuff anyway. The important bits are all new and that's what matters.