Negative feedback or "disapprove" feature?

[david (David Taylor)]

Sounds like you want this plugin

Retort - a reaction-style plugin for Discourse

Retort is a plugin which allows you to add slack-style reactions to posts [7vHi2j74Rg] Install it using the standard plugin installation instructions. It’s stable, supported, and works with the latest Discourse. Check out the code, or view it live on the demo site (note that you’ll need to make an account to use the plugin) If you have a bug or feature request, please post it here (and tag me, @gdpelican), and I’ll respond as quickly as I can. Cool features Category-specific retortions …

Unfortunately looks like it might be broken at the moment