Goodgulf:
I don't think that there are bad comments.
If something I've written strikes an emotion cord, then it strikes an emotion cord. I'd prefer it to be a good reaction but people have different tastes. I've posted stories where some people were screaming "More!" and others were saying "I hated character X" and I've appreciated both sets of comments
I have gotten comments, both here and elsewhere, that I didn't appreciate.
I don't mind negative comments, Indeed I value truly critical comments that tell me what didn't work for a particular reader rather higher than the "Good Story" comments (although those are nice too). But "This story was a sack of S**t" isn't helpful.
Even less helpful are comments explaining what an evil person i am to have written a particular story. Once, back on USENET years ago, I got a comment about a story -- it was one of the "Twins" stories I write with Sampast, I think -- explaining that I was probably a pedophile myself, but was in any case pandering to and encouraging pedophiles, and would be responsible for molestation of children by them. That was a bad comment. It also was from a person who hadn't, i believe, thought things through.
But by far the greater proportion of the comments ere are not like that, and I am glad to get negative as well as positive comments.