I wasn't logged in to hacker news, but I logged in just to comment this that yes I also absolutely hate it when I discover later on in a process that I'll have to sign up and that just puts me off.
Whenever I see this kind of practice, I see it as an indication that I will encounter similar UX all over the place, so I leave immediately and never go near it again.
Honestly, if you're thinking this is a grey pattern, then you're going to be easy pickings for any competition you may have. By all means, respect your users, but there's no need to tie your hands behind your back when most users are not HN users. If they were, javascript would probably be disabled on most sites.
As a user I really (!!) hate this, and consider it a grey pattern at best.
I greatly prefer to know up front whether I'll have to register.