It's a long thing. AD&D dwarves had high bonuses on saving throws vs magic and a 10% chance magic items would not work for them (except for things like weapons and armor). They also could only originally be fighters, and then later thieves and eventually clerics.
Supposedly it's based on the notion that Tolkien's dwarves were highly resistant to magic. Unlike elves (who learned some simple magic) dwarves did not. I'm no Tolkien scholar, so I'm not the person for details, but between Tolkien and D&D's influence on the fantasy gaming sphere, dwarves not using magic was a long standing tradition for many different systems. That seemed to be less and less as thing as other games moved away from D&Ds tropes and D&D itself moved away from antimagical dwarves.