From artist's palette to Snoopy's pellets: art that depends on disregard for copyright

Three paintings, described as "rare examples by the Mexican border-artist formerly known as El Hombre Sin Nombre" ("The man with no name", perhaps a nodding allusion to Clint Eastwood's The Good, the Bad and the Ugly persona?), have been found this year.  They are described as " unlicensed velvet art", "low art" or "border pop".  According to John Bear,

" ...no other medium better captures the zeitgeist of the mid-20th century than unlicensed velvet art, though purists will argue that the it is usually painted on felt board.

Also called “border pop,” the medium espouses a high reverence for the television shows and films that helped shape the culture of the ’50s, ’60s and ’70s. Its blatant disregard for international copyright law can be seen as a metaphor for America hegemony in the world. The medium was dominated by artists living along the United States-Mexico border, imparting it with an insider's love for American popular culture but also the critical eye of someone living on the fringe.

Border pop celebrates bright, pretty images and ease of production—that is, a tendency toward long brushstrokes and stripped-down color schemes. This technique not only allows the artist to get 10 more done before dark, but it has had the surprise effect of rendering the paintings highly resistant to the abuse and neglect they usually endure".

“Snoopy Having a Moment of Humble
 Acceptance and Gratitude
in His Time of Darkness”

By way of example, Bear explains the illustration on the right as follows:

"“Snoopy Having a Moment of Humble Acceptance and Gratitude in His Time of Darkness” eschews the stark political undertones usually present in border pop. Hombre chooses here to present a Snoopy as Christ motif. The muted grays of the lovable pooch’s face at first seem overly simple, but they betray a deep spiritual and philosophical pain. Snoopy gazes upon his dish with eyes that ask, “Should I eat my food pellets now or save them for later?” The bluish aura surrounding him suggests a deeply disturbed psyche. The deep black background represents the uncaring world. It is a masterpiece. Hombre works outside of his comfort zone but produces a work that is as beautiful and poignant now as the day it was created.

Snoopy gazes upon his dish with eyes that ask, “Should I eat my food pellets now or save them for later?"".

Can a case be made for this to be transformational use under US law?  Arguably the transformational context is provided by the caption rather than by specific reference to the underlying work.

Source: "Border Pop: Three lost examples emerge in 2010", by John Bear, posted on Alibi, 30 December 2010