I have a dissenting opinion, actually, for a number of reasons:
1. People that are new to the site probably haven't seen the question and answer before (I'm talking about newbies other than the original poster), and it will do them good to see that basic information. If it's only buried in years of threads they'll never see it unless they have the same problem, and it's useful to know it before it becomes a problem.
2. The problems are often similar to, but not exactly the same as what's been posted before. I've had questions where I did google it, but wasn't sure that my problem was quite the same, or the thread died out without any clear sense of what the problem was and how to fix it.
3. Information and best practices change over time. John Palmer's "How to Brew" is up on the web, but it's an outdated version and nobody recommends using it as your primary source anymore. Why would I trust a several-year-old thread when brewing science is improving rapidly?
4. Search sucks. It's not easy to use. Even the original poster suggests using an outside site (google) over the forum tool.
5. Relying on somebody's old thread removes the ability to actually have a discussion with members here and explaining your unique circumstances, or answering questions they might have that might affect your situation.
6. Skipping over threads that appear to ask the same question that you've seen a thousand times doesn't cost you a damn thing. Just don't click the link.
7. Posts like this make the site appear very unfriendly to new members. It might keep them from asking the question, but it will be because they're thinking "am I going to get flamed for this?" rather than "has this already been answered?" This board caters to all its members, not just ones that have been around for a while. Just because you've seen the question a thousand times doesn't mean that new members have.
8. What you're basically saying is "rather than using this forum and participating in the community, we'd prefer you go elsewhere (google) and look it up." You're basically saying "you're not welcome here".
Protip: if you don't like seeing the same questions over and over, you'll want to avoid the Beginner's Beer Brewing Forum. That's sort of what it's here for.