In my opinion the best way to get an answer to this would be to email the site moderator dang hn@ycombinator.com Perhaps the bot detection is somehow detecting on your IP or post incorrectly but only dang would be able to see what happened.
Are you sure a technical issue didn't prevent your comments from submission?
If your karma ever goes negative you will be banned. It's automated.
A new user should avoid controversial posts until they build up a karma cushion.
If an account is created and then immediately submits a link, it will often be shadow banned. I browse with show-dead on, and many posts are dead for this reason.
I haven’t noticed very many dead comments, by comparison.
When i use that account to ask questions I never get anything. In fact, I noticed that the question does not even appear on the listings. I know it prevents lots of problems but probably reduce much the retention of new users.
What I needed to do was to use that account for a couple of weeks and it was ok after. Said that, I think this is a silly way of avoiding the problem.