Yeah, I mostly agree with you too. I do think it's important to consider that diversity of interpretations, and it's why I say "has some allegorical character" rather than it having some kind of direct correspondence with real events as something like 1984 does, but the parallels to the political environment that Tolkien was personally experiencing at the time that he wrote it are too strong to ignore entirely. Although it has plenty of depth in the relationships of the individual characters to each other and their own world, it is also grounded in the intellectual ideas of early 20th century Europe and those ideas come through in the various factions and the characters that lead them or shape them. I think that kind of applicability to the political thought and events of that time can correctly be called allegory, even if he wouldn't have liked it much that I'm saying so.