Then it's like cigarettes or firearms. As a distributor you're responsible for making clear the limitations, safety issues, etc, but assuming you're doing the distribution in a way that isn't overly negligent then the user becomes responsible.

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.