That’s an interesting question. All works of art have an ideological foundation (namely that of the artist that devise them), but can these be uprooted? Is there such a thing as pure aesthetical appreciation? Let’s take a few example from the most documented period of recent times : the second world war.
Arno Breker’s sculptures have a common theme: splendor. Can you appreciate splendor without contempt for dullness? In the christian west, splendor is inextricably intertwined with purity, and here comes the slide : from appreciation of splendor to contempt of impurity and defect, to the elimination of whatever is deemed impure or defectuous. The very slide the nazis operated.
Céline’s books are now well respected where I live (france, hi!) because of the excellent job his advocates have made of propagating the idea that the man can be abstracted from his oeuvre. Anyone who has read him knows very well that it is undoubtedly the same man behind “journey to the end of the night” and “bagatelle pour un massacre” a vicious anti-semitic pamphlet.
Martin Heidegger’s work is, to this day, attacked as nazi or fascist in essence, and for good reason! : much of it (that I know of) fits the nazi ideology like a glove.
Oswald Teichmuller was a mathematical genius and a fierce nazi advocate (he died on the eastern front). To what degree can be the nazi ideology penetrate a mathematical work? To the highest : you see there is such a thing as the beginning of the last century german way of doing mathematics, and his work is one of the purest expression of this style.
Just as much of the ideology of the artist is conveyed through his work, I don’t really know, but I think much of it can be inferred, if not directly accessible, from his work. Japanes poets of the middle ages have this idea : that some situations unequivocally elicit a specific reaction from the people witnessing them. Therefore the compression of these situations as single words (cicada shell, cherry blossom, and so on) and the birth of the short poem, but that’s another story, the main point being : whole worlds are hidden in works of art, as innocent as they look.
As for the black metal band at the center of your video, it is obvious to me after reading their wikipedia page that they are racists (or nationalists as they like to call themselves, but you can’t be one without being the other, now can you?) playing dog whistle politics : it is plausibly deniable that they are racists, but the people interested in reading in their discourse that they are racist know they are.
Now you might reply that you could just listen to the music and treat the vocals as nonsensical groans (that’s not that much of a stretch) and appreciate the way it makes you feel or whatever. That’s all well, but is means that it is a poor work of art in as much as it didn’t compel you to appreciate it in its own terms, and my opinion on poor works of art is that they should be ignored.
