Plagiarism is Understandable?

Stanley Fish says yes (my emphasis added:)
If you’re a student, plagiarism will seem to be an annoying guild imposition without a persuasive rationale  (who cares?); for students, learning the rules of plagiarism is worse than learning the irregular conjugations of a foreign language. It takes years, and while a knowledge of irregular verbs might conceivably come in handy if you travel, knowledge of what is and is not plagiarism in this or that professional practice is not something that will be of very much use to you unless  you end up becoming a member of the profession yourself.  It follows that students who never quite get the concept right are by and large not committing a crime; they are just failing to become acclimated to the conventions of the little insular world they have, often through no choice of their own, wandered into. It’s no big moral deal; which doesn’t mean, I hasten to add, that plagiarism shouldn’t be punished — if you’re in our house, you’ve got to play by our rules — just that what you’re punishing is a breach of disciplinary decorum, not a breach of the moral universe.

Perhaps.  But there's a big difference between incorrectly citing a quotation or idea and brazenly appropriating whole passages, as in the shocking anecdote that opens the article.  Besides, isn't the very act of hanging out in someone's house, without knowing their rules, a moral problem?  If you waltz right by the pile of shoes in the entryway and keep yours on because you think you should be able to do what you're used to doing in your own house, you're probably the same kind of person who asks to see a friend's paper and lifts a few paragraphs because you would be willing to do the same for her.  That's not the right way to live, and boy, does it complicate the life of an English teacher!

I remember my first and most traumatic plagiarism experience as if it were yesterday.  In my first year of teaching, I read two papers that were almost exactly the same (especially absurd for an opinion paper) with only a word changed here and there.  We summoned both students to the vice-principal's office and questioned them separately.  Each broke down in tears.  I felt sorry for them, but still angry, mostly out of pride: how dumb did they think I was?!

Maybe Fish's argument is over my head (it wouldn't be the first time.)  But I have always agreed with Baba, of the Kite Runner, who says:
"There is only one sin, only one. And that is theft. Every other sin is a variation of theft . . . When you kill a man, you steal a life. You steal a wife's right to a husband, rob his children of a father. When you tell a lie, you steal someone's right to the truth. When you cheat, you steal the right to fairness . . . There is no act more wretched than stealing."