I think I begin to understand why you make again and again the point that genres are nothing special (haven't you opened a thread entitled "who uses genres", or something like that?), and I hope to make you understand why users keep rejecting this notion.
First, "genre" conveys something. It is a term used, indeed invented, by literary science, whence it has been ported to cinematography. It is not that people get high on using literary-scientific terms, rather, it is that these terms actually convey a meaning in a way arbitrary connotations don't. If you wonder about what "film-noir" means, the answer is not to poll XBMC users in this forum for their coding experience, but to look it up in Wikipedia; there, a whole world of knowledge, even magic, opens. You learn strange things: that it generated in the US; that the French got intoxicated by it, and gave it this name, which, initially was not even "film-nor"; that it is a distinct style, related artistically to expressionism; that it crossed again the Atlantic, and got even further developed in the US. After this journey, you will have learned many things about art history, cinematography, art in general. You will have learned to appreciate, among other great directors, the Ridley Scott mentioned by you. But, trust me, you will not consider making "Ridley Scott films" a filter. For by now you are able to place him within a wider context, and you have enriched yourself insofar as you know that what you appreciate in him is not a fad, not even Ridley Scott himself, but the expression of a distinst artistic style, which you recognize nor because it says so on the label, but because by now you have acquired a taste for it. And if you don't agree with the label, you re-label it. That's why users lone genres. And that's why tags shall be too difficult to catch on: despite their being technically equivalent (or, arguably, even superior) to genres, they convey no intrinsic meaning.
Secondly, users may love genres for the simpler reason that it is a tag in the NFO schema, which is freely customizable. Being an NFO tag means it can be edited while users edit the NFO file to add more info to outline and plot, the two --- and only --- places where free-form text information can be put uninhibited by size constraints. You have some thoughts of your own to add to this movie so as to inspect them again and again when browsing it in media info view: you put them there. And while you are at that, what is more convenient than to edit the genre as well, to reflect your own view as to where this movie belongs artistically? You as a developer may think in terms of filtered lists and combinations of rules, but users follow a different mental process. They try to gather information about the movie, and once they have made this information mentally their own, they write it in the outline/plot tags, and categorize the movie using mainly genres. The key here is that all that is in the same NFO file. Users think about movies while they retouche the NFO file; when done with the retouche, they think of movies no more. So even though you may be right that a filtered list is a better way to organize your movie library, users shall keep asking for the NFO file as a prime tool of keeping tabs on their collections.
Having so much extolled genres, I should add something about their use in the music NFO schema. It too uses genres. But unlike cinematography, which is literature plus visual effects, and respects, indeed often further develops, its literary past, music genres as they have developed are but a cheap attempt to sell something which is not worth a penny as something new. In the music classification schema, the whole classical musical tradition --- the whole of Beethoven, Mozart, Verdi, Pucchini, Tchaikowsky --- stands at the same level as Techno or Electronic, which should more properly be classified under Modern Music/Junk/Of The Loud Sort. So here genre carries no intrinsic meaning, making your point that genres are nothing special correct --- and the filtered list the preferred way of organizing a large music collection.
