How can they not know about the search bar? It's right at the top of the page.
Maybe they have never been on a forum before and don't know that posts are searchable. Maybe they're used to the NeoBoards. Maybe they're 12 and what is this? Maybe they're so eager and excited when they join to finally get some answers that they post without looking around a little first. Who cares? We should be giving them the tools they need to be productive members and hope that they use them. It's not their fault that the last 2000 members that joined asked the same exact questions and we're weary of answering them.
If you (in general) are going to make someone new feel like shit for asking a simple question, I think it would be in the best interest of the forum to just mosy on and ignore that instinct, and let someone who is capable of giving constructive information and guidance do it instead. Better for them to have one or two good responses than a dozen that make them feel like a stupid unwanted outsider in an elitist forum.