"as an author his livelihood would be threatened if people could freely
share his works."
Every author needs an audience. Freely sharing an author's works enlarges the author's audience. Because people understand and generally practice the principle of value for value, if they find the author's works to be of value, they are likely to compensate the author for their perceived value of the work, and because they can freely share the author's work, they are likely to share it with those who will also compensate the author and continue spreading the work.
it is important to teach others what is right and then trust them to do it