The gun manufacturers shouldn't be punished because it's not their fault someone has used their products for something bad. If manufacturers are going to be punished simply because of the way that people use their products then a lot of manufacturing companies will have to be punished as well: car manufacturers, construction tools manufacturers, medical manufacturers, etc. Are we going to punish companies that make needles because people use them for heroine? No. Why? Because those same needles can be used for tools to help people so why punish them for it?