It's Ruby WEAPON, and not Rugby WEAPON.

Everything you said sounds just about right; the weapons were trying to destroy Shinra because they were harming the planet.This thing that I'm wondering about is, why didn't they go after Sephiroth? After all, he was the one who was trying to summon Meteor so he could absord Lifestream's Power.

Also, don't forget the WEAPONS in Dirge of Cerberus like Omega Weapon. I don't know who they are and what they are for unfortunately, so someone else will have to post that.