A big one was when gwern responded to a post of mine with a vicious attack, not on my post, but on me as a person. I replied with something to the effect of, "As a rationalist, you should recognize that attacking someone has a cost, so what exactly is the benefit to you here?" He responded by saying that he just felt like it.

I disagree strongly with this characterization and feel this comment simply continues the pattern that I was criticizing. For some examples:

• Cyan on Goetz's statistical understanding: http://lesswrong.com/lw/jj6/using_vs_evaluating_or_why_i_dont_come_around/aerh
• Goetz's argument against Shakespeare: http://lesswrong.com/lw/j24/to_like_or_not_to_like/a1pj
• the 'vicious attack': http://lesswrong.com/lw/h75/optimal_rudeness/8rfh
• and let's not forget Goetz's classic http://lesswrong.com/lw/h56/the_universal_medical_journal_article_error/ (which you can see he's still complaining about in the above comment)

If people think I'm wrong, not just unnecessarily insulting, well, go through Goetz's comment and post history, starting at the beginning, and see if my summary does not strike you as fitting better than a narrative of baseless persecution. Cyan's mention of 'narcissistic injury' is right on the money.