Earlier quoted context omitted.
When has this attitude _ever_ been the solution to a shared-resource problem? I'm not being snarky, I want to know. It feels like solving traffic mortality by pasting a "drive carefully"-sticker inside the windshield, doing nothing other than establishing who is morally responsible.
Note that it wasn't proposed as a solution. Are you saying that no one should do anything good, or encourage others to do anything good, unless it fully solves a problem? I suspect that's not the point you were trying to make, but it sure sounds like that if you read your words.
Of course people should do good things, but in some cases this can lead to a false sense of security ("I'm doing the Right Thing and spreading the good word. Next issue, please!")
Where I live, we used to have signs inside the buses that read "Wait until the buss has left the station to cross the road". This was an effort to prevent accidents, but had no measurable effect other than to take the problem of the agenda for public transport officials.
With shared resource-problems, voluntary action can lead to a prisoners dilemma, where you can get ahead by _not_ doing the right thing, even though everyone is individually better off by doing the right thing.