It's not a ridiculous lawsuit. It actually needs a legal debate. Pystar is using precedent “A purchaser of a copy of a copyrighted computer program may still sell his copy to another without the consent of the copyright holder.”. However, Apple has a EULA that only allows MacOS on apple branded computers. Does Apple have the right to enforce such a EULA? That is up for debate. Microsoft tried tying Internet Explorer to Windows. This can be construed as a similar tie-in and as such an anti-trust matter.