Cowell wrote The Banshee in 1925, originally intended as a setting to a poem by John Varian, but ultimately used without the text to better evoke "primitivistic wailing." While pessimistic in tone, and a little scary, I mainly bring it up to draw parallels between Henry Cowell's era and now.
In particular, Michael Hicks' Henry Cowell: Bohemian talks of difficulties in Henry Cowell's family, as Henry was growing up, ultimately ending in his parents' divorce and his father becoming distant:
Soon Harry was a distant yet intermittently intrusive figure in Henry's life, one whose influence Henry never lost and whose absence he never overcame.
In the Strauss and Howe theory of generational patterns, four recurring groups of generations are postulated: prophet, nomad, hero, and artist. The cycle of four types repeats in order, with each generation lasting about twenty years. In today's world, prophet equals "baby boomer" i.e. those born between 1943 and 1960 (although defined slighly different than the conventional 1945-1965); nomad is "generation x", 1961-1981, hero is the older "GI generation" (for example, my parents) etc. The Clintons are probably the archetypical boomers while Michael Jordan is sometimes mentioned as the leading Xer. The Fourth Turning website says this about Nomads:
We remember Nomads best for their rising-adult years of hell-raising (Paxton Boys, Missouri Raiders, rumrunners) and for their midlife years of hands-on, get-it-done leadeship (Francis Marion, Stonewall Jackson, George Patton). Underprotected as children, they become overprotective parents. Their principal endowments are in the domain of libery, survival, and honor.
Ok, I assert that Henry Cowell is in the equivalent cohort (in the previous cycle) as today's Gen X'ers, as the "nomad" archetype. Why do I make this claim? Because I am trying to link the music of Cowell with, of all people, Eminem. On the surface, this is ludicrous; I'm comparing different genres/eras/artistic sensibilities/personal behavior etc. But then I read Mary Eberstadt's essay "Eminem Is Right," where she analyzes why today's rock and hip hop is in fact much more dark and coarse than the music of recent generations. She provides evidence of many pop stars -- black and white -- who had dysfunctional lives growing up, and who then reflect that pain and chaos in their music. The list includes Eddie Vedder of Pearl Jam, Kurt Cobain of Nirvana, the Blink-182 guys, Tupac Shakur, Korn (yes, especially Korn), Snoop Doggy Dog and finally, "Mr. Dysfunctional" himself, Marshall Mathers aka Eminem. Then in a sharp insight, she says:
And therein lies a painful truth about an advantage that many teenagers of yesterday enjoyed but their own children often do not. Baby boomers and their music rebelled against parents because they were parents — nurturing, attentive, and overly present (as those teenagers often saw it) authority figures. Today’s teenagers and their music rebel against parents because they are not parents — not nurturing, not attentive, and often not even there.
As an indulged baby boomer, I certainly experienced the former type of rebellion. Being only a couple of years older than the first Generation X kids, I've also been close to "nomad" culture as well, both through friends as well as owning CDs by Pearl Jam, Korn, Nirvana, Blink-182, Soundgarden, Eminem... To me, that latter type of rebellion seems to fit as a reaction to what happened to kids born in the Sixties and Seventies but since I had a stable family life, I can't pretend to really experience what has shaped their generation even if I can appreciate their artistry.
Finally, after writing all this, I place the ghost of Henry Cowell as a peer of Eddie and Kurt and Tupac and Marshall for a way to understand why Cowell was such the maverick and produced such compelling music (to me anyway, even if it is often so dissonant and eerie). Couldn't Cowell pass as a prototypical Seattle Grunge musician in that book cover on the left (click here to see the larger picture on Amazon)? I always think of Cowell as an old man but his youthful appearance in that picture is captivating.
My answer to why Cowell composed what he did: he's expressing the pain he (and his generation) felt growing up.