In addition to posting the previous two Wikipedia excerpts, here's a coda:
If one says something negative or critical about someone in a group who is highly valued by a majority of its members, there are usually plenty of people to come to the aid of the person they feel has been wronged. This can run from simple disagreement to outright adult bullying (innuendo, anonymous online posts, making statements like "he's the type of person who might beat his spouse" etc.).
In short, people with less power are often heavily criticized (and, ironically, called bullies themselves) if they say something about people with more power--also known as the "There's Nothing Wrong With The Emperor's Clothes! You're Mistaken!" syndrome.
I'm far from perfect. As the writer of this blog, I've been guilty of calling out certain poeterati by name if I've felt that they've been snobbish, rude or overly exclusionary--behavior that's both hurtful and severe in limiting the opening of the community to new, developing talent.
Sometimes, I've engaged in the call-out habit too much. In one case, I gave someone an unflattering nickname--a practice I stopped when the person complained about it to me privately.
But I've at least avoided saying anything about people's personal lives. My focus, when writing on poetry-related topics, stays on what people value as poets and how they define concepts such as "leadership" and "good poetry."