Imagine participating in a community, enjoying your interactions with some bright people, contributing knowledge when you can, when suddenly you find that you've become invisible. After some period of time wondering, you eventually find out that you are invisible.
It's a horrible thing to do to someone. I like many of the HN commenters, and I often learn something from reading what they've written, but I have nothing but disdain for the site itself, its mods, and its creator. They all contribute to doing this to people, though they'll brush it off as necessary automation, necessary for quality control, or some other sociopathic nonsense.