[chc]

The problem of bad questions isn't just "having stupid questions memorialized." It's that it takes away from good questions.

There is a finite number of people who can answer a question, and these people have a finite amount of time. They don't necessarily know a question is going to be bad before they read it, so if a bad question stays, it continues wasting more and more people's time, and taking time from other people who did put in the effort to ask a good question. So instead, the question is closed while you improve it, and the idea is for it to be reopened when you're done.