I don't know what Monica wrote.  I agree with you that it's hard to know why some comments get deleted. When NCR actually managed to comboxes, there was less randomness involved.  Now, there is no way to tell ho or what gets deleted.
I wish that some of the exchanges that consist of nothing more than attacks back and forth would get deleted, because I find those exchanges to be tiresome.  I also wish that homophobic and xenophobic comments would be removed, because I think that such comments do not contribute to any kind of civilized conversation.