Not all nerds like swords.
But a lot of people do like swords, so this question's worth entertaining.
There are a few things specific to nerd-dom that imbue swords with a
certain mystique:
power, history, fantasy, and legend.
Obviously, a sword symbolizes power (something appealing to anyone)
especially the nerd who may have had multiple encounters with bullies
who were bigger and stronger and more adept at using fists. But
swords are far more than simple revenge fantasy fulfillment.
The earliest swords date back to the bronze age and swords can be found in
almost every culture around the globe. A sword is a weapon, yes, but
it also speaks volumes about the time and culture of its origin. A
claymore boasts of a hard land where sheer force of will carved life
out of the highlands, while a katana speaks of discipline and duty
over emotion and self-interest.
A sword represents potential. Anyone can use a sword, just pick it up
and swing, which makes swords universally appealing...and useful.
But, mastering the full abilities of that same weapon involves years
of training. A sword, like life, demands focus.
Generally speaking, swords are objects of legend, born between hell
and hammer. A sword is more than a length of metal. It must be sharp
enough to slice silk yet flexible enough not to shatter against
steel. This is the magic of the swordsmith. And any good fantasy
story--from The Odyssey to Morte de Arthur to Game of Thrones to Star
Wars--hinges on a sword.
The edge of a sword balances life and death.
If none of that convinces you, keep this in mind when you wonder why
your nerd friend has a sword hanging on the wall. When the zombies
are breaking down your front door, a sword won't run out of bullets.