While true for individuals, companies actually have to generally warrant the things they make. This is a basic aspect of common law. In particular, Anthropic et al have not decided whether the models are products or independent agents. But under both paradigms, they would be responsible for the result. If the models are products, then a product that goes on to cause damage that was not advertised as the original purpose of the thing is completely the company's fault. As a corrolary, if the product was known to be able to cause damage (which Anthropic admits now) and the company failed to take appropriate safeguards, the company is still at fault.

In the case that the model is an agent, on par with a human employee, then once again Anthropic et al are responsible. If an employee does something wrong, the company is liable, unless you can show that the employee was sophisticated enough to take independent action. Anthropic would have to show extensive vetting of their models that the result was truly impossible to predict. Otherwise, they knowingly 'hired' an agent that was potentially dangerous. This is criminal negligence.

We don't need any new laws here. Standard ancient English common law suffices.