And while uncopyright and minimalism might seem at first glance to be unrelated, I believe they both stem from the same mindset.
Copyright stems from a protective mindset, one that believes the creator owns his work, and must protect that ownership in order to profit from said work. The creator will share his work with others, but only at a price, and anyone who takes without paying, or uses it as a basis for further creations, is stealing.
That's the copyright mindset.
The uncopyright mindset is that of someone who gives without any guarantee of profit, who lets go of ownership and believes the world owns his creation. He hopes to contribute to the world in a small way, and if others benefit from this contribution, that's a good thing. And if others use his contribution to create something new and beautiful, that's a wonderful thing.
The uncopyright creator lets go of ownership, because to hold on to ownership hurts the world, and to try to protect that ownership leads to unnecessary stress.
The minimalist also eschews ownership, at least to some degree, and believes owning things doesn't make him happy. Doing things makes him happy. Helping others makes him happy. Creating makes him happy.
It is from this place that the minimalist embraces uncopyright, and in doing so gives to the world and hopes that the world will be better for it, at least in a tiny measure.