Saying everybody should use their own names means you not only want to judge the opinions and actions of individuals, but you also want to judge them on a personal level, which should be irrelevant to... everything.
Before last year I never used my real name anywhere online, nor did I use a handle which contained any part of said name. I wrote no differently than I do now and still hold the same opinions I did previously. Who I am doesn't matter; it never should, here or anywhere else.
Of course, restricting the number of handles per person is pretty difficult without some kind of record of their real identity. But, there's a puzzle to solve!
I don't feel like I know many people on HN mostly because it's more of a forum for debate than for making casual banter, the latter being more conducive to personal bonding (at least to me). On old BBS I used to know a lot of folks and met many of them, mostly because we spent the majority of our time exchanging witty banter and such.
There are only a few names I recognize here, mostly because they have a tendency to reply to my own comments with some regularity or always post really insightful stuff.
I agree, in general, and you provided a nice argument in support of your position. Sometimes, however, you can’t help but express a strong opinion and nothing else, as I did above. Then your post shouldn’t be anonymous. Another example is when you give advice, such as in "Ask HN". Then the reader would certainly like to know your background.
--Steve