Anyway, I think, I hope, I was polite and neutral in response, said I didn't want any conflict, and left the community. Though it's hard to say because I literally felt a bit dizzy as I was typing the response. I'm certain that I partly invited the attack through the style and content of what I posted prior to the flame. I think I'm perhaps not careful enough about how I phrase things, because I'm used to hanging out with friends on the Internet, who put my 'I don't like this book' style comments into some kind of broader context.
What also scares me is that the acerbic comments I sometimes make might hit polite or shy people the way that this hit me. I hate that thought. In fact the whole event makes me a bit scared to do or say anything for fear of hurting myself or others.
UPDATE - feeling better now. Sorry about that. What a funk.