It's all too easy to blame Help Vampires for problems in Stack Overflow.
But it's not them, it's us. The people who feed them.
If the question is an exact duplicate, let them know it's an exact duplicate.
If the question is a trivial question about something from the standard library, don't forget to link to the standard library documentation while answering the question.
If someone asks "Why doesn't this code work?", and the debugging is trivial, don't just do the trivial debugging for them. Show them how they can debug it themselves (for example, tell them about warning flags).
Unfortunately, reputation goes to those who feed the help vampires, not those who help cure them. These feeders don't just get reputation from the vampire. They also get reputation from the rest of the community. (For example, 11 upvotes on an answer to a duplicate question)
I'm not meaning to be ill-intentioned towards the help vampires. Some of them haven't been taught properly how to program or how to problem-solve, and I suspect some of them are so stressed out they aren't thinking straight. Asking a question is more effort than googling, so it's not a case of laziness. But so long as the feeders deliberately don't teach the vampires how to fish as opposed to merely giving them a fish, they're going to continue to be worse off.