Personally if it was my own tribe I would do the following and people can like it or not but it's aim is to protect the platform. As much as everyone screams for decentralization it always results into a cesspool of negative and wildly crazy crap that people seriously don't need to be seeing or doing.

One of these two

• Total removal of the ability to downvote
• Or making people pay for the downvote

With

• One or a few curation accounts which find quality content and upvote it but also downvote or "mute" repeated offenders who are spamming and taking advantage of the system.

I'm sure that will spark some outrage but honestly for the most part it has to be done as a truly decentralized system just doesn't work because of human nature. I have yet to ever see a real decentralized project take off instead it's taken advantage of by greed, porn, abuse and overall negativity.