A Brief Observation on Putting Guns in your Fantasy Game

Why are guns a problem for systems designed to accommodate melee combat? Whenever we take a game that facilitates heroic action fantasy, with strong PCs tearing the enemy monsters to shreds with their swords and bows and halberds, introducing a gun just makes it… fall apart. In the confines of fantasy game-fiction, you can justify a goblin getting hit by a sword-swipe and being fine, if not a bit…