I don't necessarily agree that the commentor bears the burden of arguing that their comment is productive. Sometimes a misguided or misworded comment can lead to productive discourse. Have you ever posted a comment that you thought was wrongly downvoted? I believe each comment is neutral until it has been proven to be productive or proven to be unproductive. I believe this determination can't be made by a single individual, but by a larger group (even then, minorities may be marginalized).
It's perfectly normal for a banned account's comments to be killed - that's what happens when people break the site guidelines repeatedly.
Edit: you've been breaking the site guidelines yourself in bannable ways: https://news.ycombinator.com/item?id=25610375. That's seriously not cool. I'm not going to ban you because it doesn't feel fair to pile on, but if you don't start following the rules, we'll end up having to.
Watching you update the thread I can't reply to only proves my point.