a very succinct overview on core issues
at the GNU Project site....
by Richard M. Stallman
Copyright was established in the age of the printing press as an industrial regulation on the business of writing and publishing. The aim was to encourage the publication of a diversity of written works. The means was to require publishers to get the author's permission to publish recent writings. This enabled authors to get income from publishers, which facilitated and encouraged writing. The general reading public received the benefit of this, while losing little: copyright restricted only publication, not the things an ordinary reader could do. That made copyright arguably a beneficial system for the public, and therefore legitimate.
Well and good—back then.
More recently, humanity developed a new way of distributing information: computers and networks. They facilitated copying and manipulating information, including software, musical recordings, books, and movies, and offered the possibility of unlimited access to all sorts of data—an information utopia.
One obstacle stood in the way: copyright. Readers and listeners who made use of their new ability to copy and share published information were technically copyright infringers. The same law which had formerly acted as a beneficial industrial regulation on publishers had become a restriction on the public it was meant to serve.