Oh yes, I'm aware of that stuff. If somebody reasonably competent wanted to resolve my real name from this dummy account, I have no doubt that they'd be able to do it. My concern, however, is not that malign people reading Hacker News will try to discover who poke53281 really is (surely I'm not that interesting); rather, it's that I don't want clients Googling for my real name to easily turn up accounts of my drug-taking exploits. It is probably still possible to start with my real name and find this account, but that would be a vastly harder task -- a much smaller needle in a much larger haystack -- and again I can't actually imagine anybody being sufficiently motivated to do so.
Are you aware of browser/device fingerprinting? [0] Technology (i.e. we) has/have killed privacy (unless you take extreme steps to protect it).
[0] https://panopticlick.eff.org/