When the copy of the article was submitted to the Plagiarism Checker the overall similarity index was one hundred percent. If I received this as an assignment from a student and I was a faculty member, I would talk to the student and give them a chance to confess to copying the article. I would give them a chance to redeem themselves. I might allow them to stay in the class if they admitted to their act. I still would have to give the student no points toward the assignment. If the student did not admit to the plagiarism I would remove the student from the class and possibly report them to the university. There should be a zero tolerance policy for plagiarism of that magnitude.
If I had to explain to the student why plagiarism is dishonest, I would say that claiming to write something you did not write is dishonest, plain and simple. Plagiarism is stealing and stealing is a dishonest act. If someone takes the easy road and copies off someone else they are only making it harder for themselves in the long run. For example, in a work environment, writing skills are important. Someone who plagiarizes will not acquire these skills and make their job harder for themselves.
There are many other examples of dishonest behavior I could tell the student. One thing that is not acceptable is having someone else do your work for you. Another type of academic dishonesty is lying about citations or making up data for your assignment. None of these things are acceptable behavior for a student.