I think many here to not understand copyright law. A copyright gives one the choice as to how and when their material is circulated. That it is circulated for free in some context does not give license to others to circulate it. This is especially so with digital material.
Mom circulated some of her books for free to select people and institutions. However, when someone copied it and put it up on the internet, she made them take it down. Her books are for sale in a public context. Taking material you do not have permission to use is theft.