I think a design of a gun should not be treated as a gun. It's free speech. If CA gets their way, then it is a form of speech curtailment. How would this be different than someone explaining how to forge a gun and bullets?

This is the same as CA suing people for exercising their right to free speech under the first amendment, and the right to bear arms under the second amendment. Note that the second amendment is very clear on how the law should be interpreted, because it says “shall not be infringed” explicltly.

Unfortunately it looks like this type of constitutional violation through gun control law is normalized in a number of very blue states, and the 3D printing bans are spreading to New York and Washington states next.