Good.
It takes a looooong time to educate people and the only way they really learn is with pain. So let them live the pain of this ReplyAll hell that they have inflicted on themselves - it builds character, as I once heard.
Seriously though, what organization is stupid enough to let the Reply All function remain available ? I remember one large administration that actually had the balls to put a check on that button. It was greyed out, but you could still click it. If you did click it, you got a popup asking you to confirm that really, really wanted to be singled out for replying to everyone instead of just the sender. If you insisted, you could hardly pretend that you had done so by accident, so it was your ass if you did it wrong.
For my part, I think the Reply All button should be tightly controlled in a company, with only managerial-level staff being able to use it. And even then, lower-level staff would be excluded from the catfight.
In truth, if you do not agree with something someone sent, you answer that person and you leave everyone else the fuck out of the argument until it is solved, in which case you could eventually send a notice out to everyone with the final decision.
But everyone has to treat mail like a frakkin soapbox and broadcast their opinion to all and sundry.
Learn to speak when you have something important to say, and shut the fuck up if you just want to spout off. There's 4chan for that.