You can kill someone with just about anything, so simply saying "the brick could have hurt or killed her" is a bunch of crap. You have to look at the percentages, and I'd imagine that a brick kills A LOT less often than a firearm.
Further, she was being pelted when she stood at her window to look at or yell at the kids, and when she went outside to confront them. I can understand why, but if someone's throwing heavy **** at you, putting yourself in range of the heavy **** is a dumb thing to do.
I'm not saying these kids are in the clear, they should definitely be punished. I'm just saying that she took it WAY too far with the gun.