I'm not opposed to this at all but I question how exactly enforcement would/can work. We don't know with 100% accuracy who was responsible for Stuxnet, Flame, Operation Aurora, etc and especially with code, it is going to be exceedingly difficult in most cases to get evidence such that blame can be leveled with any certainty.
Furthermore unlike nukes it is completely impossible to verify that a country dosen't have cyber weapons. Cyber weapons can be hidden in someone's shoe, you can't do that with a nuclear arsenal.
Especially Americans need to get behind this. Right now Americans have a perceived advantage in cyber weapon technology and are thus opposed to cyber arms control.