Here from the birthplace of tunas, corn and chocolate and it is mostly the same. I think part of it is the long string of military dictatorships across the Hispanic world and the gun violence that makes it too close for comfort. Also that across Latin America most wars have been defensive wars against more technologically advanced countries so we tend to associate guns with the bad guys while the good guys fight with machetes, sickles, and forks.
(I'm not that displeased with a guns, but that is because, according to family legend, one of my ancestors was a good gunslinger; to date my great uncle still keeps his gun as a family treasure)
Asumo que sos mejicano, al menos por lo del chocolate, no sabía lo del atún

. Sigo en inglés por el foro.
I think you hit the mark here, at least partially, linking recent and ancient history with likenesses. But I also believe that there is at least two more factors included:
The first one is that D&D is about heroic actions, and there is a serious lack of heroic archetypes that fight at gunpoint. Dragons were never beaten by pistols or arquebuses, and epic fights are at swordpoint. If we see also the national heroes, like San Martín and the Cid Campeador (in Spain), they all fought with swords, rather than guns. And, as you said, guns were the bad guys weapons (Spain and their muskets against the Heroes of Independence, with spear and horseback)
It also has something to do with the US fascination with guns. They gained their freedom with them, and created their own empire with them too. I still find hard to believe how easy it is for them to buy war weapons, even at the scope of mass shootings. They created also their own gun heroes, as their Western mythology needs.
With these in account, I believe that we could explain better the disparity we see: we have lack of heroic prototypes and a general distrust of firearms, and they have a very positive reaction and several mythos about them.
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