I don’t know if posting emails is illegal or not, although I would be surprised if it were. I think it can be a useful tool in solving problems and communicating about things that are going on, but I also think that some folks have a tendency to get in too big a hurry to get really hostile about stuff.
You’re SO right about the nature and atmosphere of this board: it’s about being cordial, sharing information, and solving problems. Professionally and hopefully with a minimum of vitriol.