(the OP links to here:) http://www.copyright.gov/title17/92chap1.html#107
> Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, including such use by reproduction in copies or phonorecords or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include—
It appears to me that the OP is misreading the law. From what I can tell, the law says that if a copy/reproduction of a work is fair use...including for classroom purposes...then it is not an infringement of copyright.
The OP interprets this as: "If something is reproduced for classroom use, then it is fair use"
That is not at all correct. Check out this primer about fair use and education: http://fairuse.stanford.edu/Copyright_and_Fair_Use_Overview/...
The short summary of it is: You can't just copy whatever you want for purposes of teaching and assume that it is "fair use".
Maybe someone more well-versed in the law can correct me, but from what I can tell (I've had some education in this, but not a formal law degree), the OP is quite a bit wrong in his assumptions.