alt Hacker NewsClosed models are used to pick military targets, which seems pretty trusty to me. There was also that time where every US government employee had to send a self-written review of their work to be consumed by a very closed source model, and that too was fine. It also seems likely basically all employment data in the US federal government has been fed into a closed source model, and again this was fine according to the government.
So it seems like there is little self-hosted open weight models cannot be used for.
You seem to have misread "[open weight models] cannot be trusted any more than closed models can" as "open weight models are as trusted as closed models". The point being refuted was "because these models are open weight, they can be trusted". That does not logically follow. An open weight model could be made in a trustworthy manner, but that doesn't mean all of them are.