The Impact of Copyright on Educators

The chapter that we had to read for last week's class discusses copyright regulations and a loop hole for teachers called "Fair Use." Basically something can be copied if it is a small portion of the whole; if it would be, time-wise, impossible to seek permission, and if the copy is for only one class and one course. It is mentioned that all copies should be returned to the teacher before students leave the room with them; that the teacher should only keep one copy for herself. What is most pertinent to me was the sentence that talks about how copying pages from a workbook is not ok.
I understand that copyright was put into place to give rights to the authors of works. I can completely understand not being able to say copy an entire book and distribute that. But math workbooks?! I do not feel like photocopying workbooks destroys the integrity of the work in any way. The issue of copyrighting as presented in this course's textbook conflates "illegal" and "unethical." These are not necessarily the same thing (murder, for instance, is obviously both- speeding is certainly not unethical). It is completely unrealistic as well, since while the schools usually provide each student with some type of workbook, teachers typically run across another source that they want their students to work through. As with many things I think it is more important to follow the spirit of the law rather than the letter of the law. But clearly the number of court cases and monetary settlements reached because of copyright infringement is evidence that this is not how the law works.