when is it okay to delete a diary?

I'm in the midst of a real dilemma here and don't know what to do.  The other day I wrote a diary about body image and the response was overwhelming.  Many women wrote about their feelings of never being good enough; never quite living up to the expectations that society has imposed upon them.  The comments were tragic, inspiring, heartfelt, and most of all, supportive of one another.

Then it got ugly.  

More below.

About 2/3 of the way down the thread a male commenter stated that he was not sexually attracted to heavy women and stated some statistics about waist to hip ratio, and sexual attraction studies and stuff.  Fine.  Didn't go over that well but people were mostly civil at first.  He didn't give up.  He got nasty.  Others got nasty.

Please, if you will, follow the thread and see for yourself.  Pay attention to the time stamp, because it doesn't necessarily go in order.

The thing is, it has gotten very ugly and abusive and I am seriously thinking of deleting the diary for the safety of one of the commenters.

I hesitate to delete because there are so very many awesome stories that were shared, and, I think, some bonding went on.

What should I do.  It is still going on after 48 hours!