All these contractors who are being dumped are being replaced by full-time employees. Which is exactly the intended result. The law is intended to make employers hire people as official employees instead of hiding behind contractor status in order to skimp out on things like retirement plans and health insurance and paying their writers on net-90 terms (or worse).
The post on SB Nation, a Vox media site, said exactly that:
To comply with this new law, we will not be replacing California contractors with contractors from other states. Rather, we’re encouraging any contractors interested in one of our newly-created full-time or part-time employee positions to apply
Yes, lots of stringers will no longer get to sell an article or two a month to Vox. But they will be replaced by a smaller group of full-time employees with a complete set of benefits and enough job security that they won't have to constantly worry about making rent that month.
If you think its better for society to have a bunch of stringers who get work unpredictably, I actually agree. But in order to make that work, those people can't be living in constant jeopardy. That means eliminating worries about healthcare and savings. A medicare-for-all plan where no one has to worry about health insurance premiums, deductibles, paperwork or fighting with their insurance company for coverage would go a long way to making the freelancer model something that can actually work. But as long as we are stuck with a system where the only way to be secure is to have a full-time job, then we need laws like this that maximize full time jobs.
It is really messed up that this story was submitted by an editor at Slashdot who should know better because they are in the industry.