The article you linked is correct. Insurance companies can't price risk fairly here in CA because they need state regulator approval to increase rates. This is due to good old prop 103.

We should all be able to agree that the actuarial math backing their rates is good. What they do after when it comes to fighting policy payouts is another story

The Rolling Stone article claims that insurance companies are currently not required to disclose their math, and are fighting tooth and nail against being required to share it.