I would not for example see how my comment would be any different from any other article which you can not simply post in your blog as it is copyrightable. I do not either see for example how it would be different from say mentioning a great idea I told a friend I was going to implement yet goes on to implement it himself.
The boundaries are yet to be defined for certain, but I do not see how one can reason that others should be freely able to record my speech in a permanent form without making me know so.
If Hacker News in their terms and conditions stated that they owned all that I contributed and made this blatantly obvious, then fine, but otherwise, all that I have stated is mine, and within my authority alone.
Not that I care at all of any of it. I simply want my account to be deleted because I am tired of this place.