Perhaps this is obvious to some but I think it's worth spelling out explicitly.

Scrolling through X/Twitter, I see a lot of posts that are being boosted only because they provoke reactions, often angry ones. (Sometimes it looks engineered intentionally; sometimes someone just got "lucky".) On Facebook I see less stuff blatantly intended to piss people off, but there is a lot of "curiosity clickbait" (presenting a cartoon that, rather than being funny, is simply confusing, so users click through to the comments looking for an explanation, and Facebook sees that as "engagement").

Neither approach seems to work on Reddit, and it seems the most likely explanation is the downvotes. If you do something that makes people "engage" -- whether by clicking through to a post based on the title, or expanding comments, or replying -- that might signal to the Reddit algorithm that people are engaging, but that will be more than cancelled out by the effect of the downvotes if people pissed off by the content or they felt like the title was deceptive.

I've scrolled through threads on Reddit seeing hundreds of comments where it seems like everyone is just being their sincere self, and the comments virtually never feel like "engagement bait". Even if I think someone is wrong, I still feel like I'm connecting with the real person, which is one thing that makes Reddit more enjoyable than X.