Whether the allegations are true or not I just can't see how it's ethically acceptable (or legal for that matter) to give out an employees address to another employee. I think it was inappropriate to give that information out but there is nothing at all illegal about it.
Is the information that was given out protected, were any laws broken? No and no.
Is the address considered "public knowledge" since the property is rented and provided by our company, and therefore allows us to give it out? That doesn't matter because the information is not protected.
If anyone can give specificly what rights of B's have been violated (if any have) I'd appreciate it. None.
I suspect that A may use the information given to him to harrass B. That being said, I believe B has a right to know if his rights have been violated and if he can do anything about it. If A harasses B then B should inform the employer (who can decide if they wish to intervene or take any disciplinary action against A) and B should also file a complaint with the police. B may also wish to consult with an attorney to determine if he has a cause of action for slander against A.
Given A's behavior, particularly the video feed of B's bed when they roomed together, I'd say A is one strange dude and B is wise to steer clear.
A person, who is nice to you, but rude to a waiter, is not a nice person. (This is very important. Pay attention. It never fails.)