Well, let’s look at that again. Copying some material (I am assuming it is not a full book) is hardly a serious matter.
To give an analogy - stealing $5 from a very wealthy man is not considered as serious as stealing $5 from a very poor person. That is a holding of Moral Theology (and is age old; it is not some “new” theology from some dissenting theologian); both deprive another of what is rightfully theirs, but the wealthy person is not deprived of much, as they have much; the poor person is deprived of much because they have very little.
Copyright protection in civil law is designed to protect the writer, so that they receive just compensation. Pirating their material and selling it widely is more serious than copying for students, where one copies only a small amount, distributes it very narrowly, and receives no compensation. It should also be ntoed that often the “just compensation” is simply the acknowledgement that the material is copyrighted, and the author’s name; that is, “just compensation” often is not a cash payment.
So no, this is not a grevious matter. In most instances, the writer only asks for proper recognition of their work, and normally for students, asks no compensation, or very minimal compensation. That, too, supports the fact that this is not a grevious matter.
Schools can get into seriuous trouble -usually with a publishing house, rather than the actual writer - if they flagrantly violate copyright law repeatedly. Schools get into almost no trouble at all if they have a minor incidient, as this was. That, too supports the fact that this was not a grevious matter.