But I think this is more about preventing/limiting karma gain of an account, potentially posting/commenting limits and similar stuff.
I.e. it's more about migating the (assumed negative) effect a few people abusing comment generation could have then it is about punishing people.
You can also prevent farming high karma by just preventing flagged accounts from getting karma, given the nature of karma HN could also delay accrediting karma to accounts in general which would mean that for farmers it would take much longer to realize that they got flagged and in turn wast resources.
I assume an unfortunate number of investors track such things, however.
And in any case - this site already lets companies shill things on HN and has a whole community of investors and other startups there to back them up. I guess the transparency is what makes it not astroturfing - but it's rather close don't you think?
Rules that discourage "shallow dismissals" go too far in the other direction - and all you get is founder-template, linked-in overly congratulatory "compliments".
Rules that discourage "read the fucking article" comments go too far in the other direction - and all you get is deeply reactionary, underinformed and waaay over-confident.
Of course, the only way to know these things would be to assess based on actual merits - it doesn't seem like the site operators agree with this assessment (that degradation of comment quality is largely self-inflicted due to the curation of a "yes!" (or, equally - a "yes, and...") culture.
Tech startup culture has similar issues, so I'm not really surprised. It does suck however to lose so much respect for your colleagues (speaking hyperbolically/poetically).