I think it's fair to say that hellbanning is done to improve the site, rather than for the nefarious purposes you're trying to ascribe for it. Clearly, there are problems with it's application and transparency, but that's not the same as suggesting there's some plot here.
No, it's not fair to say that hellbanning - as implemented on HN - is done to improve the site. It's arbitrary, capricious, and hugely non-transparent.
No, I'm not suggesting a plot, but there's no natural law that says tech news sites must have a hairtrigger hellban (nor, as far as I'm aware, does any other site have anything remotely like HN's policy). Concious or not, it's a policy that HN has adopted, and it's a terrible policy.
What I'm saying is, dont confuse the motivation and the implementation. Yes, its the wrong implementation, but that doesn't mean that they apply it maliciously.