It would be off topic, but there is a bit involving a genocide from 1492 onwards in the Americas, and the 19th century portion of that, the second most brutal part of the genocide[*], wrapped up in 'westward expansion' - with the 20th century media glorification of which focusing on a 'cowboys v. indians' motif.

Suffice it to say that the Cowboy image has become synonymous with genocide for many Native People in the same way German soldiers from WWII have for Jews. Actualy Cowboys may not be the guilty party (settlers and the US Cavalry are the actual perpetrators), but the image of them has been tied up with the western occupation, even if they are really just cattle herdsmen.

[*] The most brutal part is between Columbus' second and third voyage - when Spanish slaughtered almost every living soul on Hispainola - often in horrendous ways, as recorded by the church itself. Something that began the very slow move by Spain and the Pope to eventually, a few centuries later, forbid European militaries from the New World when all other efforts at stopping excess finally failed - and thus began the creation of the 'Mission' system to colonize through the church instead. But it is also why native people are still mostly alive South of the Rio Grande and North of the Great Lakes - different means of conquest.

Truth has no value without backing by unfounded belief.
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