some fans seem uncomfortable with the idea that a poor kid could simply be good without there being some hidden noble explanation for it. so theories emerge trying to tie Dunk to famous houses, important bloodlines, or known tall characters, as though his positive character traits need to be genetically justified.
but it's clear that Dunk's story is meant to challenge the aristocratic logic: this absurd idea that virtue, greatness, and moral worth are tied to lineage. Dunk is extraordinary not because he secretly descends from greatness, but because he consistently chooses empathy, courage, humility, and decency in situations where it would be much easier not to.
so, in a way, the urge to upgrade him into secretly being noble unintentionally reinforces one of the ugliest assumptions of feudal society; and even though the books repeatedly show that nobles are not inherently wiser, kinder, or more virtuous than commoners, these fans end up accidentally reproducing bloodline determinism.
(bloodline determinism is closely related to biological determinism which has been used to justify racism, slavery, colonialism, genocide, class hierarchy, sexism, eugenics, et cetera…)
that reflects a broader instinct people absorb unconsciously, and it shows that, even if they consciously reject aristocracy, traces of this particular world view linger culturally: the idea that high status reflects inherent superiority, and that nobles are associated with refinement, leadership, honour, education, importance, strength….
commoners are often treated as mere background figures unless they prove themselves "special" in some way. so when a lowborn character like Dunk displays extraordinary moral strength and dignity, some fans reflexively assume there must be noble blood underneath it all, because they've internalised the idea that greatness must originate from better stock. that's why it can feel almost uncomfortable to some people that Dunk is just a Flea Bottom kid.
but surely, if he is fully lowborn, then his story suggest something radical within the logic of Westeros (and our own world, too): that social hierarchy is morally fraudulent, and that aristocracy is a socially constructed performance (i.e. the aristocratic class sustains itself through performance and recognition; a lord is a lord because society collectively treats him as one). Dunk's character destabilses that whole system because he possesses the ethical qualities associated with nobility while lacking any of the aristocratic status supposedly tied to them.
Dunk matters precisely because his presence challenges bloodline determinism, and echoes a broader rejection of biological determinism. he shows that honour is not hereditary and that nobility is not genetic. a person from the very bottom of society can possess more integrity and humanity than all the princes, lords, or kings combined. Dunk is not great because he descends from nobility. he is great because he chooses to be.
and sure, GRRM constantly plays with secret ancestry, so it makes sense that fans are primed to treat genealogy as the key to understanding his more enigmatic characters. and there's also a tendency in fandom spaces in general to equate narrative importance with ancestral importance, especially in the genre of fantasy.
and some fans may simply find it emotionally satisfying to connect characters into one giant dynastic web, because it creates that feeling that everything is interconnected and narratively explainable, which might make people feel safe subconsciously. but in Dunk's case, that impulse accidentally flattens the thematic point of his entire character.
Dunk's story is much more powerful if there is no reveal at all; because if he stays exactly who he appears to be – poor, obscure, uneducated, and ordinary by birth – then every act of honour becomes a direct rejection of Westeros's ridiculous obsession with blood and status.
tl;dr: Dunk is (most likely) lowborn, deal with it. and obviously headcanons are fine, but don't fall into the traps of biological determinism, kids!