I just had a classic experience with David Rozansky on Twitter. Someone recommended Rozansky as a good example of a mentor for publishing. My response was "That guy?" and a link to this thread. Rozansky immediately went into defensive mode and asked why I was so "upset" and claimed the thread was about a 13-year-old "dispute." After that he blocked me.
ETA: I did a quick check on his timeline (after logging out), and yes, he's still hijacking #askagent and giving out bad advice. He actually told someone that they should send a hand-written thank you note for any rejection.