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.
And yes, a person who eats less meat eats less meat, which is another way to say that you're introducing a non-sequitur about something which is nothing like your bus example.
I'm confused about the person who eats less meat non-sequitur. It feels like you're shoving me around a bit there.
As for the bus thing, the people responsible for reducing deaths around buses are responsible for actually solving the problem. So I agree that they should not do ineffective things like they did in your story. Meanwhile, a person eating less meat is not responsible for making sure that overall meat consumption falls.
So there's no relationship between the two situations, and that's the non-sequitur. Sorry that I didn't get this point across effectively.
And yes, I used his proposal of individual virtue as an "excuse" to raise a point about the role and reason of individual virtue in the topic at hand, it's called "having a discussion." Why should I leave virtuous people alone on the internet? Is he some kind of unassailable saint of meat-moderation who must be protected from non-sequiturs and sequiturs alike?
Whose toes are sore here?
It's far more effective to lobby for regulation than rely on individual action to solve collective action problems.
Your economic argument is naive and pretty wrong, but I'm not going to debate it here because it's not relevant to this sub-thread.