Seriously, are you really taking your posts to HN as so important than they need to receive review from peers? It's a forum. It is informal, it is not a vetted peer-reviewed journal. If someone wants to reply, they will, and it should (generally) be public (and if it shouldn't, the responder will look up your email address and send you a message, assuming that's possible)...if they don't, it's dumb to try to force them to (privately or otherwise).