"...some who get consistently flagged do act antisocial, and try to bother people."

It's a bit disingenuous to ignore that the flaggots fit that shoe too. Shoes come in pairs after all. Given that fact, the downvote pool is directly weighting the stake on one side of that dynamic. That's not the result of ignorance, but a mechanism knowingly being employed that will deliberately censor people here, and drive folks from the platform.

I think we have to ignore the baffling bullshit we're being fed and look at the actions we can observe. Bernie is one of the original ninjaminers and is possessed of a significant portion of the stake from that event. Looking at things from that perspective, it's possible that the downvote pool is entirely Bernie's baby, and thrown into HF21 as his bone for his support for other's bones being in the mix; his part in the scheme to extract money from Steem.

The 35 whales are who has designed HF21, because they hold the stake, and they are the ones in charge of development as a result.

Considering particularly the downvote pool as a critical illustration of the economic policy HF21 is intended to effect, the retention of users and their remuneration appears to be specifically intended to be reduced by the HF.

In business, profiteering is a means of extracting ROI, just as it is on Steem. The content creators can't be sold like forges or presses necessary to allow the victim business to expire, and thus enable profiteers to leave it in their rear view as they move on to the next profit center. This is a problem because it leaves the community able to remodel the platform, and create what they want it to be, and does not leave the profiteers with a clean exit.

I'm not privy to their internal communications, but their actions demonstrate their intent. Rational folks pay attention to facts that impact their circumstances. All substantial stakeholders have shown their chosen means of attaining ROI on Steem to be profiteering. The destruction of the means of production is a necessary part of that business model historically, and having a look at the history of Bain Capital or Kohlbeg, Kravis, Roberts will support this, and that leaving functional mechanisms behind creates liabilities.

People prefer to believe in a world where malice does not exist, because most people aren't malicious. Malice hurts them, and they don't like being hurt. Nonetheless, it exists, and this is why we have courts. Litigation may play a part in the future of Steem, and preventing that liability would be advisable for malicious actors. Ending Steem is one way to reduce that potential liability, to Bernie personally. He's made death threats, committed extortion (see the comments of his bots here), and sexually harassed folks, and those actions are preserved on the blockchain. Ending the blockchain will destroy that evidence.

The downvote pool seems designed to make that possible by destroying the community, the evidence, and the liability for it that might otherwise bite the profiteers in the ass later.