Tolkien disliked direct allegory but loved applicability.
Allegory imposes a fixed one-to-one meaning. Applicability allows the story to live freely and speak differently to each reader.
The Great Story should not become a rigid symbolic code where every figure means only one thing. Myth is alive because it applies itself differently at different levels.
Myth Contains Truth “In Solution”
Tolkien says myth and fairy-story must contain moral and religious truth “in solution,” not explicitly in the known forms of the primary world. (Letter to Milton Waldman, publisher, 1951)
This is excellent. It means truth is dissolved throughout the story like a tincture. It is not pasted on as a lesson. It is absorbed into the world, characters, events, colors, names, and atmosphere.