Earlier quoted context omitted.
I agree but what happens if someone posts under someone else's name? It would probably be best not to perpetuate these things and to just end the vitriol now.
Given they're active on the list in question and while the content crossed a line, the style was not out of character, nor was it later claimed to have been posted by somebody else, so I think we can rule this out.
Edit: Thank you. I was under the impression that the emails were addressed specifically to you, not a mailing list.