Theodor Adorno's aesthetic theory, as outlined in his book of the same name, argues from a dialectical materialist perspective that art is expressive (and tangible artifact of) resistance to the dominant ideology of culture. Per Adorno, (post)modernity is subjugate in stature to instrumental rationality, reducing (and flattening) all components to a means to an end. This form of rationality also pervades culture, as art is often co-opted by the culture industry to sell products and reinforce dominant ideologies through the rational consumption of said wholesale produced self-propagating, generative culture.
Harmony Korine's films, in particular "Gummo" and "Spring Breakers," have been described as subversive and challenging (stylistically in the case of the former, and on grounds of taste but not realism in the case of the latter), exploring themes consistent with a Marxian reality that can be parsed properly with the dialectic of youth, alienation, and the often perceptively latent but materially omnipresent social decay of postmodernist late-capitalism. Adorno's aesthetic theory, as well as the work of Adorno and collaborator on "Dialectic of Enlightenemnt" Max Horkheimer, can be used to view Korine's cinema as, primarily, critique of contemporary society and its dominant cultural forms in focusing on characterization that is sometimes overtly, self-parodying, and often obnoxious, but no less representative of the contradiction inherent in present day material conditions. His films often feature characters who are marginalized and alienated from mainstream society, and not always in obvious ways that as the otherwise conventional (yet inclined toward violence when an opportunity presents itself for excitement, much less than the material rewards of crime– they descend for the experience; a fundamentally postmodern response to full on alienation from reality and consequence) young people in "Spring Breakers" who turn to crime to escape their boring and oppressive lives as suburbanite university students ranging from the disgruntled church girl to the "scary" drug-using girls. These characters exist outside of the mainstream, if not challenging the dominant cultural dictates on public behavior in polite society (for example, James Franco's character in Breakers is a prominent local rapper, and this is accepted at face value despite his main trade being weapons and drugs dealing– far more lucrative and reflective of material reality than his posturing as a quirky rapper with a "hook" that he's simply "not from this planet, y'all") contra the rapidly alienating truth.
Korine likes to play with form, another thing of note here. Korine's films often use unconventional storytelling techniques, visuals that have yielded some scathing cinematic reviews of even some of his best loved films-- "Gummo" is a film concerned with "The Aesthetic of Degradation", and structurally is composed of a series of vignettes that are not linked by an overarching narrative, "Spring Breakers" uses a colorful, hyper-realistic visual style that is meant to juxtapose its subject matter with the visuals of a music video package; the kind of hyperconsumable good the film's characters are experiencing this underbelly that exposes the materialist reality to them in that format until it doesn't (and one by one they leave this wonderland of the real world, back to the bubble of the state school up the coast they came from). The sum total of these techniques is a challenge to dominant forms of storytelling and representation in cinema; an overt effort to avoid a film that would reinforce dominant ideologies and narratives and discursive tendencies around them.
Adorno and Horkheimer's work on the culture industry can also shed light on Korine's cinema in this way. Per "Dialectic of Enlightenment," they argue that the culture industry consists of rationally consumed and homogenically produced cultural forms that are designed to appeal to the masses, first as commodities, and never as intellectual or even cultural or critical rigor. These cultural forms are not only a means of social control (for example, in the case of military propaganda– why, if it did not serve the ends of the Pentagon, for example, would it fund superhero movies into the hundreds of millions annually; they can be entertaining and still be produced only for the purposes of an agenda), but also contribute to the dehumanization and alienation of individuals within society as a result (again, the end result of imperialist propaganda). Korine's cinema can be seen as a response to this homogenization of culture, forcing consumers of his work to be anything but rational with regard to the general population (you could argue his fanbase in of rational consumers of this aesthetic of degradation, but this is effect, and not cause, of material conditions– this is sought out for its truth rather than sold to them as crucial or replicative of a top-down constraint of media metaphysics by a big studio, for example), often highlighting the diversity and complexity of human experience, but in particular of a rapidly and violently alienating working class, which exists in perpetuity against the prevailing media culture to resist the standardization of cultural forms and offer a unique and challenging perspective on contemporary society.
The extent to which (post)modernist art can be utilized is largely in the phase of contradiction resolution that requires the material survey identify the conditions within which the self exists, in this case creatively; the aesthetic of degradation refers to the deliberate inclusion of elements of decay, disintegration, and deterioration in works of art as an attempt to critique and hypersatirize in the case of Korine, both as farce and tragedy, the dominant capitalist culture that prioritizes the pursuit of profit over human values and concerns. For Adorno, the aesthetic of degradation can be seen as a form of resistance to the commodification of culture. In a capitalist society, culture is often reduced to a commodity that can be bought and sold like any other product. This commodification of culture results in a homogenization of artistic expression and a reduction of art to mere entertainment. Adorno argued that the aesthetic of degradation is, both, identification and procedurally important to this creative/ideologically generative process by making active in the narrative the material conditions within which the art is occuring, as living entities in the variety set of narrative elements, in the case of Korine's cinema (the squalor of "Gummo", for example, post-apocalyptic following a tornado). Adorno's theorizing on this matter can be interpreted to take that the aesthetic of degradation is an active and productive expression of the contradictions and tensions of modern society, rather than the postmodernist tendency to languish in conditions as materially permanent. For Adorno, modernity is characterized by a tense dynamism between reason and nature, the individual and society, personal and collectivized incentive, and ultimately the social question of cultural freedom and domination by ideology, which would dampen this tension's character as materially substantive and preventing honest dialectical reasoning of the underlying contradictions of modernity.
In Adorno's view, the work of Harmony Korine could be argued thusly: traditional aesthetics emphasized harmony, order, and beauty, which he (Adorno) posited were justifying of the oppressive social and political structures of (post)modernity into the regressive and, ultimately, oppressive and engineered class unconscious present day. The aesthetic of degradation, on the other hand, rejects these traditional aesthetic norms and instead embraces disorder, chaos, and ugliness as a function of art, a utility for forcing the issue of material significance for all things holistically, within the metaphysical representation of our world in art, something Korine does, as I said, in films like "Spring Breakers" where characters are real, but surreal (as in, extra real– it speaks to a real problem and real set of material tendencies, even if this is not plausible and common person), the material variety set that dictates the way this universe is understood creatively, representationally, and productively as generative of discourse, is being asserted and strongly, and primarily as what makes his films interesting to viewers as a constituency, influencing other visual artists, etc. which, of course, ultimately is to keep the contradiction widening between real materialist rigor, and the asserted postmodern metaphysics of western liberal democracy's illusion of (entirely relative, and where that relatively comes from, which again, begs the question of real materialist rigor) material prosperity.