Artists always build on the achievements of others in some way. So, the argument for freedom says that if we the people prevent you from remixing music, words, or videos created by others we're stifling innovation and so impoverishing our society.
Look at the YouTube video "Somewhere over the rainbow", based on fusing the songs "Over the rainbow" (music by Harold Arlen and lyrics by E.Y. Harburg, and originally recorded by Judy Garland) and "Wonderful World" (written by Bob Thiele and George David Weiss, and originally recorded by Louis Armstrong). This version is sung by Israel Kamakawiwo'ole to an innovative ukelele arrangement. Renzo Schröder has provided a video accompaniment.
Could such a beautiful work have existed without remixing?
On the other hand, the argument for copyright says that if we the people let you republish for free what others have created, we're depriving artists of income for their work, so making it harder for them to spend time creating. And so out society is again impoverished.
Consider again the YouTube video. You watched it for free. None of the contributing artists received payment from you.
The proponents of freedom can say that if you liked the video, perhaps you'll one day buy a related song, concert ticket or other product that eventually lead to some cents making their way to the artists. Perhaps. Perhaps not. It doesn't matter much in this case anyway, because Harold, E. Y., Judy, Bob, George, Louis, Israel, the people who helped them and their dependents have probably received enough from historical sales for it not to make much difference to them. And Renzo shared it on YouTube for free, so he probably doesn't feel any loss.
But the proponents of copyright can ask: Whose decision is it to take that artists' works are shared, if not the artists?
So, which argument is right? If we the people prevent remixing, innovation is stifled and so our society is impoverished. If we the people allow unfettered republishing, artists are deprived of a source of income that might be their best chance of supporting their craft; and so again our society is impoverished.
I think both arguments are right. And I don't know what we the people should do.