Another possibilty: Dwarves use axes because Dwarves favor heavy armors.
Generally, you learn to use weapons and armors that either work well against those you train with or against your most common foes. Sometimes, there is no difference, but that isn't always the case.
Mongols, for instance, wore silken undershirts to protect warriors against the damage barbed arrows (and other, similar projectiles) do...because they usually fought people who used barbed arrows.
Dwarves would be used to using weapons that do well against medium to heavy armor and shields, and as many historical reinactments have shown, axes and maces (and simliar weapons) actually do better against such armors than swords because of the way they concentrate mass at behind the weapons' striking surface. An axe might cleave open or a maul might dent armor that would deflect a blow from a sword.
So, after learning how to fight other Dwarves, Dwarven warriors would find that their weapons were still effective against other races- they'd just have to use different tactics to get those foes into the proper position...
Generally, you learn to use weapons and armors that either work well against those you train with or against your most common foes. Sometimes, there is no difference, but that isn't always the case.
Mongols, for instance, wore silken undershirts to protect warriors against the damage barbed arrows (and other, similar projectiles) do...because they usually fought people who used barbed arrows.
Dwarves would be used to using weapons that do well against medium to heavy armor and shields, and as many historical reinactments have shown, axes and maces (and simliar weapons) actually do better against such armors than swords because of the way they concentrate mass at behind the weapons' striking surface. An axe might cleave open or a maul might dent armor that would deflect a blow from a sword.
So, after learning how to fight other Dwarves, Dwarven warriors would find that their weapons were still effective against other races- they'd just have to use different tactics to get those foes into the proper position...