I always forget about that angle, that Lucas ultimately okays or nixes pretty much anything that has to do with Star Wars. Even if it was "underground", Lucas probably has the resources to hunt them down and blow them out of the water. Therefore, he OK'd this.
As for why? With the plethora of fanfic out there (EU books, etc.) I think he feels that the more Star Wars, the better. I don't see a really high standard being kept.