A couple of comments. First, people extrapolate from this one incident to make generalizations about blocking lists. If so, they'd be drawing very wrong conclusions about lists such as SBL or Blitzed OPM.

Second, from reading the linked news articles, I'm having difficulty working up a lot of indignation. Seems like a bunch of people were acting like dicks here.

Finally, I hope you recognize the right of people to publish (non-defamatory) information, regardless of its stupidity. I think Joe can do whatever he wants to do with his block list. I can (and do) choose not to use it. (I do think it's a good idea to publicize questionable list policies so that people can better make those decisions.)

Some time back, I blogged an article on the topic of bad block list policies.

It's relevant that he contacted Joe Jared from his
personal address
after finding his work address blacklisted. The response was to
blacklist his personal address as a "nitwit spammer"! What is someone
to do?

This isn't one of the one-spammer-poisons-a-netblock cases. Rather,
it seems just plain spiteful. And months later, after he's left the
company, how can it be justified?

It's not about whether it's legal to be spiteful with
blacklists. What bothers me in part is the process of how it happens,
and the easy to abuse power placed in someone's hands.