Bingo. Likewise if Best Buy started selling proprietary software in violation of its license.
You've hit exactly the right point: nobody is exempt from copyright. This is why all of these arguments about the GPL being unenforceable seem idiotic to me. You comply with the license, which in most cases means you comply with the relevant sections of USC -- or whatever alternate license has been approved by the rights holder. Only the holder has a right to the software they create; rights are reserved by default. A selectively permissive copyright license is functionally no different, even though it makes other legal allowances and restrictions than the defaults. Nobody has a right to the code in any form otherwise, and I sincerely doubt any GPL enforcement case falls under a situation where a "resolution of necessity" would have been reasonable to justify appropriation and license violation. There's always an option: comply with our license for our software, comply with someone else's for their software, or write and license your own software.