It's probably better to call this a 'Beta IPO' filing. This is a fairly new system that allows companies to work out bugs in their filings before they open it to public viewing.
Clearly anything on Hacker News and other news outlets isn't an actual secret!
"Clearly anything on Hacker News and other news outlets isn't an actual secret!"
But it could have been intended to be.
Assuming this is a serious question: yes. The secret aspect only applies to the process leading up to the IPO.