This is your chance to say the things that are true, but that no one ever says. No need to be awful about it, but the next time that one person does or says something passive-aggressive, call him/her on it and say loud enough for others to hear that the passive aggressive attitude is one of the reasons that have led to your leaving. If you can do all of that with a smile or even a laugh (as in "none of this matters anymore"), then that's the best way.