My 1k account got banned before this account was created. I don't mention its name because I don't know if the moderators would ban me.

They would.

I made some experiments. Mix of fear of cross voting and anti spam technique I guess.

When you get banned I'm pretty sure you get banned. So that account/accounts is/are closed but the person is banned. Clearly it's not enforceable but indicating a new account of a banned person would surely have that account removed?

Not necessarily. If we see some sign that the user is turning over a new leaf, we're happy to give another chance. The purpose of banning isn't to cast anyone out, it's to preserve a place for civil, substantive discussion. I sometimes hear people defend uncivil comments by saying that other people shouldn't be so fragile. But it isn't individuals who are fragile—it's the community.

Plenty of users have gone from being banned or penalized to being positive contributors on HN. Once someone understands why the rules and moderation are the way they are, things almost always go fine. It's not, for example, about "needing to sugarcoat everything", "avoiding uncomfortable truths", or any of that kind of explanation. It's about the extreme weakness of the social contract on the internet.

Will see. I have no doubts that mods are doing that they sincerely think is the best, but I have my doubts if that's indeed the best.