Is it legal/allowed for my school to take action on happenings on FaceBook?

Both parties are wrong I'd say. Shouldn't be making things like that so open. I've heard that colleges and some jobs look at sites like facebook to see what you are like. And think of it as, say someone in your family got murdered. Someone close to the killer puts on facebook, my cousin blasted some dude up. Then others said something like "they got him good!" Wouldn't that make you mad? Sure its no where near as serious as your situation, but the point is that people protect whoever they're close with. And then again its stupid of the school to do that. Its like, get a life, or something like that. Just don't mess up school over something like that.