I had the exact same issue as well. And I'm working on a hacker news Chrome extension as well which caused me to refresh too many times. The blocking doesn't seem to be time limited. I restart my router which assigns me a new IP.

For development, you can copy some hacker news sample pages and put on a local server and edit your hosts file and use your fake local hacker news (at least for the parts that is possible) then you can refresh as much as you like.

I hope people behind Hacker News give us some details about how things work so we can adjust the extensions, etc...