It appears to be open, the most recent post was 27 minutes ago. I'm not sure what OP is referencing.

> what happened that Hail Corporate was killed?

As has happened with other subs, it began to be full of extreme opinions on one side and the reasonable posts were downvoted in the other.

So, you end up with a toxic environment where it is difficult to have a rational conversation.

I am really grateful for the moderation done in Hacker News. I have seen also that kind of strategy tried here. Controversial posts being promoted to the main page and fake extreme opinions show up in the comments. But, the post is flagged a later removed. That stops the anger to spread to real users.