I said about 27 times* during the whole Seven situation that he was not banned for quoting a PM. He was suspended for repeatedly breaking other rules, mostly about insulting people, and acting like a jerk. Part of the ‘acting like a jerk’ involved quoting a PM, but only a part, and as other mods have noted there is not a rule against it.
Her motivation was obvious, magellan01.
twickster could have warned DudleyGarrett in private, but we don’t like to do things that way and Dopers have come to expect that warnings are always made public. She didn’t have to reveal specifically what he said, but if she hadn’t, she would have been asked. Going to that level of secrecy over “shove it up your ass” seems a little ridiculous. She went the simple route and just told people why he was being warned. If she’d disclosed personal information about DudleyGarrett you’d have a case that his privacy was violated. But she didn’t.
We want people to respect each other’s privacy and everyone prefers these messages not be posted. Like twickster said, she had a judgment call to make on this issue because there were conflicting values. If posters feel they’re being harrassed by other posters via PM, they can talk to a mod about it. I’ve had people share PMs with me this way, and I think this is a similar situation.