Mkay, here's a brief rundown of a situation I was in, and my 2cp on these.
I was hanging out in my usual kiting spot in Tactics, left from the zonein. Was medding up and dropped a Diaku Scimitar on the ground. Within 2 minutes a Gladiator aggrod me, saying "You dare challenge me?" or some nonesense. Now this totally baffled me, since in the 20+ hours I've spent kiting in this spot, I have never seen a roamer. I had been sitting in the middle of the sand pit when the Gladiator aggrod me, and I have no clue where she came from.
Now... on to the weapons...
a) Pure Vendor Trash
b) Pure cosmetics to make the ogres look fancy
c) Damage-nerfing weapons (considering how crappy the dmg/dly is, and the fact they wield them, they would tend to do less damage than they would normally hand to hand, one would think)
d) Unknown quest (some kind of trigger, or was that just a fluke?)
e) Something to annoy players.
I highly doubt it's a tradeskill thing, since every single Diaku drops a weapon.