Well, it's helpful to keep in mind the main goal here, which is providing young people with an education (and providing society with educated young people), not having the students produce brilliant original work (it's just a school assignment, after all). Being a little more pragmatic, rather than flunking half the students for a prolonged period, probably gets you further.

Of course students need to be thought that plagiarism is not ok, again the question is how to teach them best. The threat of big punishment is not necessarily an effective mean towards reducing "crime". The article also hints at the fact that the cause of the plagiarism is not so much malice, as difficult surcomstances, and a lack of knowledge/skill in students (though the main example around which the article centers, may not give a strong argument for this)