There is no "general fantasy tropes". there is Tolkien-ish, d&d-ish,J-rpg, anime-ish fantasy and etc. sure, most of them overlap.
Cannibal elves, evil carp, magma, gemstones and golbins allied with clownic fun forces of happiness make sure that Dwarf Fortress's fantasy trope is original. OF COURSE it made from the same pieces than the D&D trope is made and the same pieces that tolkien's trope is made, but THAT configuration that is DF is original.
I don't think you're using the term "trope" here in the same way. A trope is not an entire setting; it is a creative device or convention that is likely to be familiar to an audience because it appears in other, similar works. Elves liking trees is a trope. Dwarves having beards is a trope.
Different tropes are widespread and familiar to different degrees among different audiences. I take shiruba's label of "general fantasy tropes" to mean "a large set of tropes commonly seen/expected in works of 'traditional' fantasy fiction." These would be the tropes that lie within the overlap you mentioned. Taken with this intended meaning, shiruba's statement makes complete sense.
If you want to know more, I recommend wasting several hours of your life on
TV Tropes.
Backing off from linguistic nitpicking, I do disagree with shiruba's assertion that for vanilla DF to be vanilla, racial differences must be "hard-coded." If it's hard-coded, it's not moddable (since the source is not open), and anything like that is going to be the way it is in *any* version of DF, not just unmodded/vanilla. If elves liking trees comes about in an emergent way based on racial sphere preferences or somesuch, that provides a mechanism that is an
alternative to hard-coded behavior. If the racial sphere preferences or whatever are moddable (in the RAWs), then the emergent behavior can be changed indirectly.
Of course, emergent behavior is tricky because you don't control it directly. If the attempts to elicit the emergence of desired behavior fail, one can always fall back on some degree of hard-coding (and sacrifice flexibility).
Okay, maybe that's still linguistic nit-picking. Sort of.