Great chapter. Loved how Harry got back at the Ravenclaws. He pointed out some things that has nagged me about Hogwarts teachers. They were always painted as caring towards their students and knew what was going on, but that was rarely ever the case. Luna was a perfect example. No one helped her most turn a blind eye to what was going on. I'm glad that someone stood up for those who can't stand up for themselves. I don't think the professors realize that turning a blind eye to things will lead to more Tom riddle wanna be.
Yes, something I always found curious. The staff would rebel against Umbridge, and support Harry once the truth came out in OotP but not before, as you point out they refuse to help Marietta... but they do nothing to help Luna, or even help Harry in CoS, GoF, and OotP until it is too late and he no longer needs it. BJH