

Copyright and License terms are two different categories of law. Copyright is an idea created and enforced by the laws of the country which has jurisdiction. Licenses are a contract between two parties and is covered by contract law.
A thing can be unable to be protected by copyright and also protected by the terms of the license that it is provided under. If a project contains copyrighted code that does not mean that you cannot be held to the terms of the license. Your use of licensed works is granted under the agreement that you follow the terms of the license. You cannot be held liable for copyright violations for using the code, but using the code in a manner that is not allowed by the license makes you liable for violation of the contract that is the license agreement.






Plagiarism and copyright violation are two different things, one is ethical and the other is legal.
Copyright has a body of case law which helps determine when a work significantly infringes on the copyrighted work of another. Plagiarism has no body of law at all, it is an ethical construct and not a legal one.
You can plagiarize something that has no copyright protection and you can infringe on copyright protection without plagiarizing. They’re not interchangeable concepts.
In your example, some institutions would not allow such a device to operate on their property but it would not be illegal to operate and the liability would be on the person and not on the oven.
To further strain the metaphor, Linus is saying that you can use (possibly) exploding ovens, because he isn’t taking a moral stance on the topic, but you are responsible for the damages if they cause any because the legal systems require that this be the case.