There’s some misinformation floating around regarding Lemmy not having a karma system. While many have discovered otherwise, this is for those who may not have.
While it’s not exposed in the Lemmy default user interface, Lemmy does have a fully functional karma system and it is visible in third party clients such as WefWef and Memmy.
Do with that what you will.
Not every sub is for “quality content”, some subs are intended for debate / dialogue between people that disagree with each other, and use the downvote button to mean “disagree” … which means if you are coming for a quality dialogue, you tend to only see a quality monologue unless the user base is split 50/50 on the topic, which is rare.