You are partly right. Even in the Pentagon with people having the highest security clearances possible, only those who have a "need to know" are allowed access to certain information.
I've made a lot of mistakes in my life, but divulging classified or even sensitive unclassified information was not one of them, and I worked with lots of it. No one I knew would have done anything like that either.
That general had a perfect right to be angry with the leaker. People don't take these things seriously enough any more from the sounds of things.
We have people in congress leaking information and we have people lower on the totem pole working with similar data who wouldn't think of doing such a thing because they know they would be canned or severely disciplined, government employee or no. There is a code of honor about the whole thing, too, but honor doesn't play as well in these times.