Kbin and Lemmy are better built than Reddit in several ways to handle those behaviours to a certain point:
Karma: it's hidden on Kbin, and I can't find it on Lemmy. So, there is no pressure to post or comment something. Do you know that feeling on Reddit when you have 500 karma, you write a comment, and later you have 480 karma? That's what I'm talking about.
Instances with their own rules: every instance has its own administrator(s), and they can set different rules for them and apply them. Some are more tolerant than others, so in the end,your experience depends on what instance your account is. Besides, some instances don't have downvotes, so that's a big plus too.
People: we all, or the most of us, know how situation was on Reddit, how we struggled to make our experience be positive, with no success. Because we know that, we don't want that situation to replicate on these places. It's difficult sometimes, but we do what we can.
Defederation: as someone said here, if situation inside an instance is too hard to tackle, to the point that those bad entities harass users on other instances, then defederation is key, until the situation comes back to normal.
And there are other things, like algorithm (or lack of), code open sourced to fork if you wish, etc.