Two years after I graduated high school, I went back to my original high school (the one I was in before I dropped out) to visit one of my teachers. We ate lunch together in the staff lounge. There were a couple of new teachers there but most of them were the same as when I attended, and they all pretty much remembered me. Man, were they ever cursing. It was shocking to hear it. It was like, because I was alumni they didn't care anymore.
I've also worked in some corporate offices and it's pretty much the same deal. Management all have potty mouths, but when it comes to PR they act all nicey nice.
Yeah, the principal was out of line, but I think her biggest mistake was sending the e-mail to the wrong person. In the professional world, when it comes to internal affairs a lot of stuff is off the record, and a lot of it would make your jaw drop.
And let's not even mention the kinds of e-mails that get forwarded around.