Hellbanning is necessary because of the low barrier to creating a new account. You are assuming that all users are well-intentioned and can be reasoned with, but this is simply not the case. Any sizable only community will develop a number of hard-core anti-social trolls exhibiting behavior which they can only undertake online (because in real life they would get their asses kicked on a regular basis). When said trolls are also hackers you need some relatively automated and powerful tools to keep them in check. It's unfortunate that there is some collateral damage, but please understand that the choice is not between new users being inconvenienced for not, the choice is between HN being a place where civilized discourse can exist and spiraling towards a 4chan-like atmosphere.