Why Tolkien "cordially disliked allegory"?

Tolkien declared in his introduction to The Lord of the Rings: I cordially dislike allegory in all its manifestations, and always have done so since I grew old and wary enough to detect its presence. 

This seems straightforward, and we would expect Tolkien to eschew allegory altogether. 

But there is a sense in which this statement is misleading if taken generally, because Tolkien himself wrote and published allegory; especially the short story Leaf by Niggle - which does not make much sense unless understood as a Christian allegory. 

Nonetheless, Tolkien was sincere in his dislike of allegory when this was falsely attributed. 

And this can be understood if The World as depicted by an allegory, is contrasted with The World as depicted in the kind of mythopoeic fantasy that Tolkien most desired to write. 

The core difference is that an allegorical world points to the modern mundane (and therefore materialistic) life as its reference. 

In other words; an allegory deliberately and by intention maps-onto everyday life - whether that world be politics, recent news, social phenomena and trends, or something else. 

The idea with allegory is that the reader should enjoy the story, which might be a fairy-tale-like beast fable such as Animal Farm; but also be aware that the story has another kind of ordinary reference; mapping outside-itself and more superficially - nearer to our everyday world and this life as we know it. 

By contrast; the kind of mythopoeic writing favoured by Tolkien aims to build a fantasy world that points-at a spiritually-deeper world. A world of enchantment, of greater phenomena and enhanced experiences. 

Mythopoeia could be characterized as aiming to have a world underpinned by perspectives that induce mystical, religious, spiritual, magical associations in the reader.

If the invented world is regarded as a subcreated world; then an allegorical subcreation intends to make us think more superficially and materialistically; whereas a mythopoeic subcreation wants us to be aware of depths below. 

An allegory aspires to be "relevant"; whereas mythopoeia aspires to be profound. 

 

Tolkien's vehemence against allegorical interpretations of The Lord of the Rings Therefore, mythopoeic fantasy needs actively to avoids pointing the reader at modern, mundane life; because an allegorical reading of LotR would subvert its intention - by making the story "relevant" it makes it superficial; it ceases to be profound, enchanting, mystical.

It is evident, therefore, that if the reader starts suspecting allegory of a fantasy, and begins interpreting a story in terms of mundane modern references - this will sabotage the possibility of the kind of mythopoeia Tolkien desired to write with Lord of the Rings.  

For readers to be encouraged to "interpret" LotR as an allegory, would prevent the book from being experienced as the kind of story that Tolkien most wanted it to be. No wonder he so much hated and resisted this false attribution! 

Considering matters more generally, it can also be seen the price that is always and inevitably paid whenever story-makers (whether in novels, movies or on television) strive to make fantasy narratives relevant to "real life". 

This is one reason why recent mass media have degraded mainstream fantasy worlds such as Doctor Who, Star Trek and Star Wars - by striving to make them "relevant" to the mainstream modern materialistic world we inhabit. 

When storylines are made allegorical of "current issues" - and even more strongly when directly didactic elements are inserted - all hints of profundity and enchantment are excluded. 

In general the serious problem with allegory for modern alienated mankind; is that it pushes us back into exactly that shallow, boring, mundane life that we were hoping to transcend by our experience of "other worlds"