Are you seriously implying bitcoin will succeed or fail basing on what we do? If it's a good idea then people will use it even if everyone here start screaming "do not use it"
If it's a good idea, welcoming communities will form around it too, that's part of the process. And members of these communities will warn each other when they are offensive to newcomers, etc. You are actually thinking in reverse, people will use it even if you
scream "do not use it", but not everyone will do it, since it contributes absolutely nothing.
It's analogous to the usability topic. If it's a good idea, people will build user friendly tools around it. I would fail to comprehend how not contributing to building such tools (because it's a good idea anyway?) would help. Same with this.
Bottom line is, you don't need to respond if you think it's a dumb question.
Excessive nursing of dumb people makes dumb people even dumber in the long run. This is like Education 101.
Although I think you are right on that general idea, I'm not sure it maps well to this topic. What does Education 101 tell you about this kind of reaction? The asker could
have been offended. Geek communities quickly form this kind of cultural barrier around themselves, and it's one of the problems. I know people who are very competent at their own thing and yet are unable to read any kind of documentation about an external subject prior to taking action on it. It's a personality trait. Yes, I can't relate to it either, but that is the reality.
Positive encouragement to take the proper action doesn't have to involve excessive nursing. Gabi's "Newbies should read faq and guides before opening threads" is IMO one of the good responses to such people and it's pretty much neutral. There are people who would be offended by even this, but we aren't payed for PR anyway, so I think it's a good line to draw. Again, no one is required to respond either.