There is already a total count of up- and downvotes, but please never add karma to Lemmy. We don't want to deal with karma farmers and minimal karma requirements to post. I don't care about the moderation issues because karma brought more harm than good. Please never add that bloody dreadful thing to Lemmy. I already saw a bunch of people supporting adding karma to Lemmy, which will turn Lemmy into a cheap Reddit clone and karma-farming hell. Please, never add karma to Lemmy. I beg you. No more karma hell.
The Reddthat instance that I'm on also has disabled down voting which I'm also all for. On Reddit, down voting very often became a tool for vocalizing what you disagreed with rather than a low effort or inappropriate post.
I am MAJORLY against disabling downvoting. This results in VERY toxic comments and content being pushed to the front and click bating content, which is what was witnessed on YouTube and Facebook, and is still a major problem. This is because youtube and other sites measure popularity of content not just by upvotes but by interaction. If you click on and/or comment on something, that's interaction. Youtube does not care about the quality of content and comments, so long as it is interacted with and shared. This means that inflammatory comments and content and click bate get lots of angry comments and rage clicks and click bait gets clicked because it's click bait and it registers and popular content that will generate lots of interaction so it gets pushed to the forefront. On reddit this kind of content gets largely weeded out by a quality check, downvotes. While no system is perfect, this allows the community to say "no, ok, just because I clicked on this and maybe even left a comment, this is NOT good content, and should not be shared with others." It also is a natural scam and spam filter that allows the community to quickly shoot down anything that is obviously spam.
Youtube comments were extremely toxic for this exact reason for a long time after the change. They had to implement a lot of changes to help reduce that toxicity, and probably went back to considering the downvotes despite not showing the count.
I agree with you from the context of YouTube, and perhaps I am misinderstanding Lemmy, but I don't think it has any sort of similar engagement mechanism?
The issue with YouTube is the desire to push "engaging" content even if that content sucks or is actively incendiary.