Would his blood be on the hands of the researchers who trained that model?
If we were facing a reality in which these chat bots were being sold for $10 in the App Store, then running on end-user devices and no longer under the control of the distributors, but we still had an issue with loads of them prompting users into suicide, violence, or misleading them into preparing noxious mixtures of cleaning supplies, then we could have a discussion about exactly what extreme packaging requirements ought to be in place for distribution to be considered responsible. As is, distributed on-device models are the purview of researchers and hobbyists and don't seem to be doing any harm at all.
Should the creators of Tornado Cash be in prison for what they have enabled? You can jail them but the world can't go back, just like it can't go back when a new OSS model is released.
It is also much easier to crack down on illegal gun distribution than to figure out who uploaded the new model torrent or who deployed the latest zk innovation on Ethereum.
I don't think your hypothetical law will have the effects you think it will.
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I also referenced this in another reply but I believe the government controlling what can go on a publicly distributed AI model is a dangerous path and probably inconstitucional.