Fuzzy definitions of intellectual property?

In an article that started off with plagiarism by chemistry students, one finds the text:

Welcome to the sometimes confounding topic of plagiarism in the cut-and-paste Internet era. While most seem to agree with the notion that plagiarism — taking the work of others and presenting it as your own — is wrong, everyone from national experts to professors and students say the vast quantities of easily accessible online information coupled with fuzzy definitions of intellectual property and common knowledge make this matter thorny. Many campuses are grappling with it.

Plagiarism is copying without attribution. One can plagiarize works protected by copyright and one can plagiarize public domain works. Fuzzy definitions of intellectual property have nothing to do with plagiarism.

The article ended with the text:

“My concern is if we don’t do something, it explodes eventually,” says McCabe. “It gets to the point where everybody is plagiarizing and you no longer know whose paper you are grading.”

So, the endpoint is a world wherein everyone is copying everyone else, and there is no originality left.