They are intrinsically an offensive weapon, as they damage, not protect, which is what I think of when I think of defense. That is why I think it is funny. A shield I would consider a "Defensive Tool", or body armor, or armor plating. A projectile that damages flesh not so much.
ETA Not sending an email, don't need to sign my name
Edited, Jan 10th 2013 4:06pm by stupidmonkey