It came as something of a shock to me when I first heard someone express the idea that Native American rock art was simply graffiti. I was at first tempted to write off such a judgment as simple ignorance, which after all is a correctable condition. Subsequent encounters with such derogatory expressions, however, convinced me that something more nefarious was at play; the denigration of the ancient art was really a signal or gesture which betrayed an underlying attitude, rather similar to a poker player's tell which inadvertently reveals the player's hand or intention. Such judgments, often asserted rather aggressively, are really just expressions of underlying patterns of racism and xenophobia. The implications of such critical derision is that Native American rock art and likely other examples throughout the world was the casual production of slackers incapable of producing real Art. I've been inclined a few times to offer some historic facts in rebuttal, as well as mentioning the rather wide range of artistic values in actual modern graffiti, but I think it is pretty much a waste of time to try to maintain a dialogue in the face of willful ignorance.
An interesting and persistent variation on the theme of rock art as graffiti is the belief that the ancient designs were produced by someone other than Native Americans. Here is a passage from Discovering North American Rock Art (quoting Steward from 1937) which pretty well sums up the loopy wing of rock art interpreters:
... Popular fancy musters petroglyphs in support of theories abandoned by science half a century ago. It offers them as proof that Egyptians, Scythians, Chinese, and a host of other Old World peoples, including the Ten Lost Tribes of Israel, whose fate continues to have absorbing interest to many persons, invaded America in ancient days. It claims them to be markers of buried treasures, signs of ancient astrology, records of vanished races, symbols of diabolical cults, works of the hand of God, and a hundred other things conceived by feverish brains...The chapter authors, Hyder and Loendorf, go on to note that:
Sixty and more years after noted anthropologist and archaeologist Julian Steward made this statement, we would need to add only aliens from outer space for Steward's assessment to remain true...I would add that is seems rather likely that a substantial portion of the Lost Tribes theorists are contiguous with those who would have dinosaurs and cave-dwelling humans living in the same era. Perhaps the tell might be extended even a trifle further to include the fervid supporters of a Trump presidency.