Well, you can have whatever policy you like, of course, but I don't think "retaliating" in a way that escalates the situation (and drags more people into it) is a terribly useful way to react to something which, at the end of the day, is just a moron being rude. I don't think an "expectation of privacy" is the issue; it's a question of whether something's a sensible reaction, rather than whether it's permissible under whichever RFC covers Geek Social Interaction.