Yes, the catapult was the weapon. I have inside knowledge on this, don't ask. (we're having a catapult-building competition, the Highland Fling, at our Celtic Arts Festival next month, there are a lot of entries. Its a guy thing...)
But first, the catapult was designed to look terribly large and threatening, 20 feet long and 10 feet high, but not to have any actually significant flinging power. It could shoot a teddy bear about forty feet. This got surreal, my friend who was firing teddy bears at one point had to perform an act of civil disobedience and lie down in front of the 'pult to prevent members of the BLACK BLOC from hauling it off and trying to do real damage with it. (And by the way, he was arrested but not charged with anything. The cops dropped him off forty miles from QC at 2 a.m. )
Singh had absolutely nothing to do with the catapult!! He didn't organize it, plan it, pay for it, use it or anything. He was seen looking at it and laughing. That's the extent of his involvement. A whole bunch of people have signed a statement that they were the catapult mob and that Singh wasn't involved. (One of the confessors, the shadowy secret godmother of the project, is JUDY REBICK, a well-known union activist and now TV opersonality.