Copy rights don't exist -- they are complete legal fictions, currently designed to make sure the Disney Corporation can keep profiting from any configuration of 3 intersecting circles.
The only valid concern here is attribution rights, which are natural in a social sense, and act as a consumer protection against fraud. Plagiarism is usually defined more in terms of proper attribution than "copying", because uses of the terms with the root "copy" are so ambiguous and problematic (esp. in the digital age) as to make it unusable in enforcement, even when limited to enforcement of social norms. Quotes, citations, footnotes, bibliographies, and now hyper-links are all valid methods to lend attributions to originating sources. None of these attribution methods were used in this case, which makes finding of fault very simple.
Please don't let this debate devolve into "fair use" definitions, which are still ambiguous after centuries of contradictory court findings. Defining fair use as less than 140 characters, a few sentences, a chorus, a bar, a frame, an act, or a page are all equally subjective and ambiguous. The variety of potential valid reuse contexts are just far too great to simplify by numerical means. Copyright laws in the U.S. have always been in conflict with the First Amendment, and "fair use" has never been a sufficient work-around.
Let's talk about attribution rights and forget the copy right fiction.