Anthropic has alleged that this model is much more dangerous than other currently available models. Their CEO has said so publicly multiple times. It's like asking why cesium isn't banned if nuclear missiles are banned.
(whether Mythos is actually that dangerous is beside the point; considering that Anthropic claims that it is, it makes sense to regulate it)
(whether Mythos is actually that dangerous is beside the point; considering that Anthropic claims that it is, it makes sense to regulate it)