There are several snarky knee-jerk reactions in the comments here, but state assemblies pass things all the time that ultimately fail to pass or get vetoed. Now the public will debate it, contact their state senators to give their opinions...it's all part of the process.
California constantly passes all kinds of weird, pointless, and burdensome gun laws. There are so many of them, and they're so poorly written, that no lawyer in the state who can confidently tell you what's legal and what isn't until a court chimes in. There's no meaningful process around any of that.
The only thing that's different about this one is that it mentions a technology geeks care about. But I doubt that's enough. As another commenter noted, you can no longer hide behind "we have no technology to distinguish between guns and non-guns". We have AI that's supposedly PhD-level and will soon automate all jobs. Looking at STL files sounds like a job.
That's actually one of my fears about LLMs: they make thought policing cheap. There are profound privacy and cost barriers to having a Facebook employee review all your private messages. There are no such barriers to having a robot watch all your IMs in real time.
If this fails it'll be because the tech industry expresses disapproval too loudly to ignore.
The legislators don't care about the underlying criticism. Almost no legislators have ever used a 3d printer or written any software, beyond maybe simple assigned programs if they had a required intro-to-programming course. Few are "tech" people. The rest don't understand this technology, or any technology really, beyond it being a black box for specific purposes. They see 3d printing and plastic guns and think something must be done, because the 3d printing black boxes are producing dangerous weapons.
Describing California as "the Europe of the United States" ignores its essential narcissism -- defining California in terms of Europe would be met with contemptuous pashaws, even if the balkanized ethnic enclaves found there, at a scale larger than anywhere in the U.S. -- not even New York, resemble Europe. The Asian communities will also wonder if you can find Vietnam on a map -- would guess you think it is in the Mediterranean.
Europe favors comprehensive regulation, with laws or directives dealing with families of related issues. California does regulation in a very American way, with individual bills targeting specific issues. It just does more of that than the average state.
and I would imagine close to 100% of the US 3d printing nerds that live there have the means to easily move to another state and continue their 3d printing nerdom.
There is a reason why California is leading the nation in migration out of the state.