I'm not a doomer but I honestly don't understand this argument. If releasing model as open source helps researchers determine if it's safe, what about when it's not deemed safe? Then it's already out there, on the hard drives of half of 4chan. It's much easier and cheaper to fine-tune a model, distil and quantize it and put it on a killer drone, than it is to train it from scratch.
On the other hand I totally relate with the idea that it could be preferable that everyday has access to advanced AI and not just large companies and nation states.