I think that people should have some rights in terms of expanding on what she wrote, for instance. But that encyclopedia was just reiterating what had been written in the seven novels. It wasn't adding anything new.
(As for character control: Rowling spent years building her universe before writing a single word. I think it would be pretty awful if she didn't get some sort of recompense for the people who use those years of planning and make a quick buck off of it. But I'll admit that I don't know whether or not copyright law protects something as conceptual as a character design.)