Closed models are also used for nefarious usage.
You could limit what it was training on in the first place - however that would damage capability - and it's difficult to curate the input, especially when the models can do 2+2. ie the choice is between model power and safety - and they choose power and everything else is a sticking plaster.
One thing I find amusing is the refusal of a lot of the models to now output a lab based protocol because of fears about 'weapons' - yet I can buy a textbook or simply read papers for exact protocols.
I find it hard to reason that a person who isn't motivated enough to read a paper or buy a book, is somehow enabled to make a biological weapon because of ChatGPT - despite them needed to buy a whole bunch of specialist equipment and reagents to do it.
Are there a whole bunch of proto-terrorists who are frustrated simply because they don't know where to start?
Maybe the only place their might be radicalized teenagers - but then that's perhaps a reason for keeping them off the internet full stop :-)
The knowledge to create weapons is already widespread, the idea that terrorists need chatgpt for that is laughable