"Although Tolkien stated that he wanted the story to continue and grow, Christopher 'Gollum' Tolkien doesn't, and guards the legacy with zeal."
He didn't you know. Neither is Christopher in any way Gollum- like.
If Tolkien really had wanted others to write stories set in his world, he could have forgone copyrighting his books; made them 'public domain'. He did not. What's more, it was Tolkien himself who set up his Estate, whose purpose is to carry out Tolkien's wishes as set out in his will. (this is the function of anyone's estate; including yours and mine, if we so wish). One of Tolkien's wishes was for copyright to remain with his family.
What Tolkien wrote was that he left all of his unpublished works - his 'literary assets' - to his trustees, requesting them to allow Christopher full access, "in order that he may act as my Literary Executor with full powers to publish edit alter rewrite or complete any work of mine which may be unpublished at my death or to destroy the whole or any part..." etc.
If Christopher were Gollum-like, we would not have Tolkien's translations of Sir Gawain and the Green Knight, Pearl, and Sir Orfeo (1975). Nor The Silmarillion (1977), nor any other of Tolkien's posthumously published works. Nor would Christopher have given permission for other scholars to edit his father's works; such as Beowulf and the Critics (Michael Drout) nor Roverandom (Hammond and Scull), nor create such a visually stunning work as 'JRR Tolkien: Artist and Illustrator'. (ditto)
Name-calling is not very constructive, don't you think?
- and hardly helps an already tottery claim.