Why should the community trust just one account to control all this?

There is very little trust required since it all goes back to DHF quickly. The balance of the account is usually zero.

I have chosen to not support the proposal to stabilize HBD until the tyrannical rogue downvotes by this account are stopped

Do what you like. I have confidence that the majority of Hive stakeholders will act to support the value of their investment (which this proposal does). If I didn't, I wouldn't be invested in Hive.

one big account's opinion can overrule what the community has valued the post to be.

Again, you seems confused about what is going on. The community decides whether or how to vote on a particular post. When people decide to upvote, not upvote, downvote, or not downvote, those are all community decisions. Including mine, I'm part of the community too. Then the blockchain adds up the votes and decides what reward to pay out.