When Dumbldore is temporarily removed, Ron laments that he was their only hope. I'm sure that Ron assumes that Dumbledore, leading the rest of the competent wizard faculty and staff, was working, unbeknownst to the students, to solve the mystery and save the muggle borns and all that. They have all the resources and knowledge that Harry and Co spend the whole book trying to get. We see that they are preparing the cure for the petrifications. Otherwise, we don't actually see them Professer D and the rest doing anything about the attacks, except making sure everyone avoids walking alone.
Then, when the mystery becomes a real tragedy and Ginny is taken into the Chamber. The teachers all drop any attempt to actually save her in order to get their (long merited) revenge on Lockheart for being an all-talk poser. If they wanted to make a fool of him by sending him into a danger he was terrified of, but wasn't actually life threatening, that would be one thing. But they send him to accomplish a task they know he is perfectly incapable of, when a girl's life is at stake, just because they have grown tired of his bragging. At that point, I can no longer believe that they have been doing anything but reacting to the events. If that is their plan, no wonder Ginny and Tom weren't caught before.
Someone tell me how I am supposed to think of any of the teachers as anything but immature cowards? Are they all terrified because the headmaster isn't around?
I can't think of an explanation that doesn't reflect poorly on the teachers Rowling clearly wants me to at least respect. The other explanation doesn't reflect very well on Rowling herself. She really wanted Lockheart to go down into the chamber with them (he makes great comic relief) and couldn't, or didn't think of another way that would be consistent with the teacher's characters. It might have been okay for Snape, assuming he is truly a heartless villain who wants Ginny dead. But it makes no sense for the rest of them to agree to it, unless they are less intelligent than Ron, who can see through Lockheart's bragging.