It's not about changing the gun nuts' minds, like you said, it's not going to happen, but there's a whole lot of people out there without strong feelings one way or another, who don't know about what laws are out there, and who are potentially open to being persuaded to your way of thinking, and if you want to convince them of your position, you don't want to give your opposition an easy opportunity to derail the conversation and make it look like you don't know what you're talking about and they do.