First, I agree with you, though I don't call it "bad legislation", I call it lobbyism. But there is one tiny nitpick to disagree with, aside from another user pointing out that there are even simpler ways for obtaining firearms.

> If I wanted to make something resembling a firearm

While I totally agree with you that this is all about lies, there is still one difference in that most regular firearms are metal-based. With 3D printing one could print plastic or similar materials.

Again, I am not saying this is a reason to explain this lobbyism here, but we also need to be objective when debunking the lies of the other side. For instance, one difference is metal detection (naturally plastic-based weapons would also tend to break more easily, so this whole legislation is a total lie to begin with anyway; California is currently broken. I am surprised about that, usually you'd think other US states are more broken, but California is now in the top 3 lobbyist-controlled states - and from there the disease spreads slowly).