I don't think that "acceptable/unacceptable" is a sensible way of thinking about it; it's just axiomatic that there are some irreversible situations that cannot easily be gotten out of - time moves forwards, not back.

We might be able to move the bar, and that might be a good idea (welfare programs, etc), but that's all we can do, and there is clearly a point beyond which trying to rescue people is throwing good money after bad.

There is no way of preventing a human from damaging themselves in the general case (whether that damage be intentional or unintentional; I'm not moralizing here.).