You are correct to assert the problem is complex. It took me 5 years to understand why witness votes are weighted as they are because of the complexity of the machinations underlying Hive governance. A colluding oligarchy with 30 100% weighted witness votes can elect a consensus that only the whole platform could oppose by colluding, and that is absurdly improbable.
Downvotes aren't the same thing as not upvoting. IRL you either buy a product or don't. You aren't able to lower the price of the product the manufacturer gets for it. Downvotes do that. They aren't the opposite of upvotes. They are an upvote against that content being published. As you say, the default is no votes at all. Upvotes encourage and reward creators, and lack of votes discourages and fails to reward them. Downvotes actively suppress them. They destroy the value of their content to the creators, like if a competitor for your job was able to reduce your wages in order to make you quit so the job would become available.
That's why they are necessary on Hive, because that financial disincentive nominally counters spam, scams, and plagiarists. Unfortunately it also successfully does the same thing to people that speak out against prevailing policies. If scientific debate worked that way we wouldn't even have clubs, pointy sticks, or edgy rocks.
Censorship is necessary for Hive to succeed, because Hive cannot succeed unless spam, scams, and plagiarism are prevented from monetizing content. Censorship of content that isn't spam, a scam, or plagiarized can also destroy Hive's success, and that degree of success depends on how censored Hive is. There are other metrics that Hive's success depends on, so censorship resistance alone isn't the only thing that determines whether Hive succeeds, and to what degree.
I would submit based on the token value, user metrics published daily by @arcange, and personal experience that Hive is barely able to not completely fail, and that mostly due to Splinterlands today. Wanting Hive to do better isn't something horrible. We all want Hive to do better, eh? However for an oligarchy that captures ~90% of rewards, better can be the enemy of good enough, and only dissenters that do not threaten to tip that boat are tolerable. I also submit I am pretty stupid, because it took me 5 years to grasp how the governance of Hive is maintained through the weighting of witness votes that enable the oligarchy to be assured of their control, and neither an upstart whale nor an agitated demos of plebs can threaten that control.
It even took two years after Sun Yuchen demonstrated how that control was exerted, by tipping that boat with the Founder's stake, before I figured it out. Clearly I am not a credible threat to the extant oligarchy, and doubt they will care what I say one way or the other. The real blackpill is knowing that you are irrelevant no matter what you know, say, or do, and then you die.
LOL
Regardless that we will be able to wrangle over minutiae forever, I appreciate your considered opinions on censorship and how it affects Hive. We may not agree on everything, or even anything, but at least on Hive we can have that discussion and our accounts aren't banned.