It's one thing to experiment with turning a coin out of restructuring elements from another work off your own bat.
It's another thing to develop that work from a space that forbids it, with the assistance of people who agree with those rules and another thing altogether to try and make money from someone else's work when it was developed in a space that forbids it and the person who made it sticks to those rules on principle.
Lucas didn't steal from Herbert etc, he emulated them and was fortunate enough to make more money from the emulation.
Faneditors don't steal from Lucas, they borrow and sometimes get more satisfying results using the same intellectual equipment.
If I construct a garden from discrete cuttings from my neighbour's plants with his knowledge and make an arguably better garden, my neighbour still has his garden.
If some bugger digs up my garden and sells the plants on ebay, my garden built on a blind eye turned by my neighbour is spoiled, it needs to be repaired and my neighbour may no longer allow me take cuttings if it encourages theft in the community.