so let me get this straight

We don't consider it a "clean room rewrite" if a human who has previously worked on a codebase and has clearly learned how something is supposed to work does a full rewrite, even if the code looks different, right? Because it's basically a derivative work?

But if the code is laundered through a plagiarism machine instead of a human, we're golden and we can disenfranchise any past contributors who expected their code to be distributed under a certain license/attribution?

I mean, I'm not a copyright lawyer, but if, say, Wine contributors were former MSFT employees who had worked on the proprietary parts of the operating system and had intimate knowledge of its internals, that would cause problems for Wine, wouldn't it?